Single Operator Intracranial Medical Device Delivery Systems and Methods of Use

ABSTRACT

A rapid exchange microcatheter for accessing the intracranial neurovasculature. A side opening through the sidewall is located a first distance proximal to the distal-most tip. A proximal opening located proximal to the side opening is a second distance from the distal-most tip. A distal, reinforced catheter portion extends between a distal end region to a point near the side opening. A proximal, reinforced catheter portion extends a distance from a point near the side opening towards the proximal end of the catheter body. The side opening is positioned within a gap between a proximal end of the distal reinforced catheter portion and a distal end of the proximal reinforced catheter portion. A payload of a cerebral treatment device is housed within the lumen proximal to the side opening. Related devices, systems, and methods are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 15/875,214, filed Jan. 19, 2018, which claims the benefit ofpriority under 35 U.S.C. § 119(e) to U.S. Provisional Patent ApplicationSer. Nos. 62/448,678, filed Jan. 20, 2017, and 62/517,005, filed Jun. 8,2017. The disclosures of the applications are hereby incorporated byreference in their entireties.

FIELD

The present technology relates generally to medical devices and methods,and more particularly, to single operator intracranial medical devicedelivery systems and their methods of use.

BACKGROUND

Acute ischemic stroke (AIS) usually occurs when an artery to the brainis occluded, preventing delivery of fresh oxygenated blood from theheart and lungs to the brain. These occlusions are typically caused by athrombus or an embolus lodging in the artery and blocking the arterythat feeds a territory of brain tissue. If an artery is blocked,ischemia then injury follows, and brain cells may stop working.Furthermore, if the artery remains blocked for more than a few minutes,the brain cells may die, leading to permanent neurological deficit ordeath. Therefore, immediate treatment is critical.

Two principal therapies are employed for treating ischemic stroke:thrombolytic therapy and endovascular treatment. The most commontreatment used to reestablish flow or re-perfuse the stroke territory isthe use of intravenous (IV) thrombolytic therapy. The timeframe to enactthrombolytic therapy is within 3 hours of symptom onset for IV infusion(4.5 hours in selected patients) or within 6 hours for site-directedintra-arterial infusion. Instituting therapy at later times has noproven benefit and may expose the patient to greater risk of bleedingdue to the thrombolytic effect. Endovascular treatment most commonlyuses a set of tools to mechanically remove the embolus, with our withoutthe use of thrombolytic therapy.

The gamut of endovascular treatments include mechanical embolectomy,which utilizes a retrievable structure, e.g., a coil-tipped retrievablestent (also known as a stent retriever or a Stentriever®), a woven wirestent, or a laser cut stent with struts that can be opened within a clotin the cerebral anatomy to engage the clot with the stent struts, createa channel in the emboli to restore a certain amount of blood flow, andto subsequently retrieve the retrievable structure by pulling it out ofthe anatomy, along with aspiration techniques. Other endovasculartechniques to mechanically remove AIS-associated embolus include ManualAspiration Thrombectomy (MAT) (also known as the “ADAPT” technique). MATis an endovascular procedure where large bore catheters are insertedthrough the transfemoral artery and maneuvered through complex anatomyto the level of the embolus, which may be in the extracranial carotids,vertebral arteries, or intracranial arteries. Aspiration techniques maybe used to remove the embolus through the large bore catheters. Anotherendovascular procedure is Stentriever-Mediated Manual AspirationThrombectomy (SMAT) (similar to the Stentriever-assisted “Solumbra”technique). SMAT, like MAT, involves accessing the embolus through thetransfemoral artery. After access is achieved, however, a retrievablestructure is utilized to pull the embolus back into a large borecatheter.

To access the cerebral anatomy, guide catheters or guide sheaths areused to guide interventional devices to the target anatomy from anarterial access site, typically the femoral artery. The length of theguide is determined by the distance between the access site and thedesired location of the guide distal tip. Interventional devices such asguidewires, microcatheters, and intermediate catheters used forsub-selective guides and aspiration, are inserted through the guide andadvanced to the target site. Often, devices are used in a co-axialfashion, namely, a guidewire inside a microcatheter inside anintermediate catheter is advanced as an assembly to the target site in astepwise fashion with the inner, most atraumatic elements, advancingdistally first and providing support for advancement of the outerelements. The length of each element of the coaxial assemblage takesinto account the length of the guide, the length of proximal connectorson the catheters, and the length needed to extend from the distal end.

Typical tri-axial systems such as for aspiration or delivery of stentretrievers and other interventional devices require overlapped series ofcatheters, each with their own rotating hemostatic valves (RHV). Forexample, a guidewire can be inserted through a Penumbra Velocitymicrocatheter having a first proximal RHV, which can be inserted througha Penumbra ACE68 having a second proximal RHV, which can be insertedthrough a Penumbra NeuronMAX 088 access catheter having a third proximalRHV positioned in the high carotid via a femoral introducer. Maintainingthe coaxial relationships between these catheters can be technicallychallenging. The three RHVs must be constantly adjusted with two handsor, more commonly, four hands. Further, the working area of typicaltri-axial systems for aspiration and/or intracranial device delivery canrequire working area of 3-5 feet at the base of the operating table.

The time required to access the site of the occlusion and restore evenpartially flow to the vessel is crucial in determining a successfuloutcome of such procedures. Similarly, the occurrence of distal emboliduring the procedure and the potentially negative neurologic effect andprocedural complications such as perforation and intracerebralhemorrhage are limits to success of the procedure. There is a need for asystem of devices and methods that allow for rapid access, optimizedcatheter aspiration and treatment to fully restore flow to the blockedcerebral vessel.

SUMMARY

According to a first aspect, disclosed is a rapid exchange microcatheterfor accessing the intracranial neurovasculature. The microcatheterincludes a catheter body having a sidewall extending between a proximalend to a distal-most tip, the sidewall defining an internal lumen havingan inner diameter sized to house a payload of a cerebral treatmentdevice. The microcatheter includes a distal opening from the internallumen near the distal-most tip, a side opening through the sidewall ofthe catheter body and a proximal opening located proximal to the sideopening. The side opening is located a first distance proximal to thedistal-most tip of the catheter body. The proximal opening is located asecond distance from the distal-most tip of the catheter body. Themicrocatheter includes a distal, reinforced catheter portion extendingbetween a distal end region of the catheter body to a point near theside opening; and a proximal, reinforced catheter portion extending adistance from a point near the side opening towards the proximal end ofthe catheter body. The side opening is positioned within a gap between aproximal end of the distal reinforced catheter portion and a distal endof the proximal, reinforced catheter portion. The payload of thecerebral treatment device is housed within the lumen proximal to theside opening.

The first distance can be between about 10 cm to about 20 cm. The seconddistance can be greater than about 20 cm. The distal opening can belocated at the distal-most tip of the catheter. The side opening can besized to pass a guidewire having an outer diameter that is equal to orless than about 0.018″. The proximal, reinforced catheter portion can beless flexible than the distal, reinforced catheter portion. The distal,reinforced catheter portion can have a first reinforcement structure.The proximal, reinforced catheter portion can have a secondreinforcement structure. The first reinforcement structure can becoupled to the second reinforcement structure by a rigid coupler. Therigid coupler can form a reinforcement structure that is different fromthe first reinforcement structure or the second reinforcement structure.The first and second reinforcement structures can be similar instructure to one another or different structure. The first reinforcementstructure can be less rigid than the second reinforcement structure andthe second reinforcement structure can be less rigid than the rigidcoupler. The first reinforcement structure can be a coil and the secondreinforcement structure can be a coil, wherein a pitch of the coil ofthe first reinforcement structure is greater than a pitch of the coil ofthe second reinforcement structure. The first reinforcement structurecan be a coil and the second reinforcement structure can be a braid.

The coupler can have a window aligned with the side opening. The sideopening can be configured to allow a guidewire to pass into or out ofthe internal lumen while preventing the payload from engaging orsnagging on the side opening as it is moved through the internal lumenduring deployment. The sidewall of the microcatheter can further includea lubricious, tubular liner and a reinforcement layer positioned overthe tubular liner that is more rigid than the tubular liner. Thereinforcement layer can include a first reinforcement structureextending within the distal, reinforced catheter portion. The secondreinforcement structure extending within the proximal, reinforcedcatheter portion can have a distal end, the proximal end of the firstreinforcement structure separated from the distal end of the secondreinforcement structure creating the gap. A short, tubular rigid couplercan be positioned over the proximal end of the first reinforcementstructure and over the distal end of the second reinforcement structure.The coupler can have an elongate window extending through a sidewall ofthe coupler. An outer jacket can be positioned over the coupler and thereinforcement layer. The coupler can be sized to span the gap such thatthe elongate window of the coupler is aligned with the gap while atleast a first portion of the coupler is positioned over the proximal endthe first reinforcement structure and at least a second portion of thecoupler is positioned over the distal end of the second reinforcementstructure. The tubular liner and the outer jacket can seal together atthe elongate window forming a dual-laminate membrane encapsulating theside opening of the microcatheter. A slit can extend through themembrane allowing for the guidewire to pass through the side opening.

The inner diameter of the microcatheter can be less than about 0.035″ toabout 0.0165″. An outer diameter of the catheter body can be less thanabout 0.050″ to about 0.023″.

In an interrelated aspect, disclosed is a system including the rapidexchange microcatheter and a distal access catheter having a flexibledistal luminal portion having a proximal end, a proximal end region, aproximal opening, a distal end, and a lumen extending between theproximal end and the distal end. The lumen of the distal access catheteris sized to receive the catheter body of the rapid exchangemicrocatheter.

The distal access catheter can further include a proximal extension thatis less flexible than the flexible distal luminal portion and isconfigured to control movement of the distal access catheter. Theproximal extension can extend proximally from a point of attachment withthe flexible distal luminal portion adjacent the proximal opening. Theflexible distal luminal portion can have an outer diameter at the pointof attachment that is larger than an outer diameter of the proximalextension at the point of attachment. The proximal extension of thedistal access catheter can be solid or hollow.

The distal access catheter can be assembled with a tapered inner memberforming an assembled coaxial catheter system. The tapered inner membercan include a flexible elongate body having a proximal end region, anouter diameter, a tapered distal tip portion, a distal opening, and asingle lumen extending longitudinally through the flexible elongate bodyto the distal opening. The tapered inner member can include a proximalportion extending proximally from the proximal end region to aproximal-most end of the tapered inner member. When assembled, thetapered inner member can extend through the lumen of the distal accesscatheter and the tapered distal tip portion extends distal to the distalend of the distal access catheter. The flexible elongate body of thetapered inner member can include a proximal opening sized to accommodatea guidewire. The proximal opening can be located through a sidewall ofthe proximal end region of the flexible elongate body. The proximalportion can be a hypotube having an opening in fluid communication withthe single lumen of the flexible elongate body.

The system can further include a guide sheath having a working lumenextending between a proximal end region and a distal end region, thedistal end region of the guide sheath having at least one opening incommunication with the working lumen of the guide sheath. The guidesheath can have a working length sufficient to have the distal endregion of the guide sheath positioned within a portion of a carotidartery and the proximal end region positioned near a femoral accesssite. The flexible distal luminal portion of the distal access cathetercan be sized to extend coaxially through the working lumen of the guidesheath and pass through the at least one opening of the guide sheathtelescopically extending the distal end of the flexible distal luminalportion beyond the distal end region of the guide sheath. The catheterbody of the rapid exchange microcatheter can be sized to extendcoaxially through the lumen of the distal access catheter extendingcoaxially through the working lumen of the guide sheath such that thedistal-most tip of the microcatheter passes through an opening at thedistal end of the distal access catheter. The distal end region of theguide sheath can further include an occlusion balloon on an outersurface configured to arrest flow through a vessel upon expansion of thesealing element. The cerebral treatment device can be a stent, stentretriever or a flow diverter.

In an interrelated aspect, disclosed is a method of accessing theintracranial neurovasculature using a catheter system. The methodincludes positioning within a vessel of a patient a guide sheath havinga working lumen in communication with a port at a proximal end. A distalend of the guide sheath is advanced at least to an internal carotidartery. The method includes inserting a distal access catheter throughthe port into the working lumen of the guide sheath, the distal accesscatheter having a lumen and a distal end. The method includespositioning the distal end of the distal access catheter beyond thedistal end of the guide sheath. The method includes inserting amicrocatheter loaded with a payload of a cerebral treatment devicethrough the lumen of the distal access catheter. The microcatheterincludes a lumen, a distal end region having a distal opening from thelumen, and a side opening from the lumen located a distance proximal tothe distal opening. The payload, when loaded, is housed within the lumenproximal to the side opening. The method includes advancing themicrocatheter loaded with the payload through the lumen of the distalaccess catheter until the distal end region of the microcatheter isadvanced at least to the distal end of the distal access catheter. Themethod includes deploying the payload of the cerebral treatment devicewithin the intracranial neurovasculature.

The distal access catheter can include a flexible distal luminal portionhaving a proximal end, a proximal end region, a proximal opening, thelumen extending between the proximal end and the distal end; and aproximal extension extending proximally from a point of attachmentadjacent the proximal opening. The proximal extension can be lessflexible than the flexible distal luminal portion and is configured tocontrol movement of the distal access catheter. The flexible distalluminal portion can have an outer diameter at the point of attachmentthat is larger than an outer diameter of the proximal extension at thepoint of attachment.

The distal access catheter can be assembled with a tapered inner memberforming an assembled coaxial catheter system. The tapered inner membercan include a flexible elongate body having a proximal end region, anouter diameter, a tapered distal tip portion, a distal opening, and asingle lumen extending longitudinally through the flexible elongate bodyto the distal opening; and a proximal portion extending proximally fromthe proximal end region to a proximal-most end of the tapered innermember. When assembled, the tapered inner member extends through thelumen of the distal access catheter and the tapered distal tip portionextends distal to the distal end of the distal access catheter. Theproximal portion of the tapered inner member can be a hypotube having anopening in fluid communication with the single lumen of the flexibleelongate body. The flexible elongate body of the tapered inner membercan include a proximal opening sized to accommodate a guidewire. Theproximal opening can be located through a sidewall of the proximal endregion of the flexible elongate body.

The method can further include arresting blood flow by expanding anocclusion balloon on an outer surface of a distal end region of theguide sheath.

In an interrelated aspect, disclosed is a method of accessing theintracranial neurovasculature using a catheter system including loadinga guidewire within a microcatheter. The microcatheter including a lumen;a distal end region having a distal opening from the lumen; and a sideopening from the lumen located a distance proximal to the distalopening. The guidewire, when loaded, is positioned within the lumen ofthe microcatheter such that a distal end of the guidewire extends outthe distal opening and a proximal end of the guidewire exits the lumenat the side opening. A payload is housed within the lumen proximal tothe side opening. The method includes inserting into a vessel of apatient the microcatheter loaded with the guidewire and the payloaduntil the distal end region of the microcatheter is advanced into theintracranial neurovasculature.

The method can further include positioning within the vessel of thepatient a guide sheath having a working lumen in communication with aport, the working lumen having a distal end. The method can furtherinclude inserting a distal access catheter through the port into theworking lumen of the guide sheath, the distal access catheter having alumen and a distal end, the distal end of the distal access catheterextending beyond the distal end of the guide sheath to at least a levelof the internal carotid artery. The distal access catheter can furtherinclude a flexible distal luminal element having a proximal end, aproximal end region, a proximal opening; and a proximal extensionextending proximally from a point of attachment adjacent the proximalopening. The proximal extension can be less flexible than the distalluminal element and configured to control movement of the distal accesscatheter. The proximal extension can have an outer diameter at the pointof attachment that is smaller than an outer diameter of the distalluminal element at the point of attachment.

The method can further include positioning within the vessel of thepatient a guide sheath having a working lumen in communication with aport. A distal end region of the guide sheath can further include anocclusion balloon on an outer surface configured to arrest flow througha vessel upon expansion of the sealing element.

The distal access catheter can be assembled with a tapered inner memberforming an assembled coaxial catheter system. The tapered inner membercan include a flexible elongate body having a proximal end region, anouter diameter, a tapered distal tip portion, a distal opening, and asingle lumen extending longitudinally through the flexible elongate bodyto the distal opening; and a proximal portion extending proximally fromthe proximal end region to a proximal-most end of the tapered innermember. When assembled, the tapered inner member can extend through thelumen of the distal access catheter and the tapered distal tip portionextends distal to the distal end of the distal access catheter. Theproximal portion of the tapered inner member can be a hypotube having anopening in fluid communication with the single lumen of the flexibleelongate body. The flexible elongate body of the tapered inner membercan include a proximal opening sized to accommodate a guidewire. Theproximal opening can be located through a sidewall of the proximal endregion of the flexible elongate body.

In an interrelated aspect, disclosed is a method of accessing theintracranial neurovasculature using a catheter system includinginserting into a vessel of a patient a distal access catheter assembledwith a tapered inner member forming an assembled coaxial cathetersystem. The distal access catheter includes a flexible distal luminalelement having a proximal opening into a lumen extending between aproximal end and a distal end; and a proximal extension extendingproximally from a point of attachment adjacent the proximal opening. Theproximal extension is less flexible than the distal luminal element andconfigured to control movement of the distal access catheter. Theproximal extension has an outer diameter at the point of attachment thatis smaller than an outer diameter of the distal luminal element at thepoint of attachment. The tapered inner member includes a flexibleelongate body having a proximal end region, an outer diameter, a tapereddistal tip portion, a distal opening, and a single lumen extendinglongitudinally through the flexible elongate body to the distal opening;and a proximal portion extending proximally from the proximal end regionto a proximal-most end of the tapered inner member. When assembled, thetapered inner member extends through the lumen of the distal accesscatheter and the tapered distal tip portion extends distal to the distalend of the distal access catheter. The method further includes removingthe tapered inner member from the lumen of the distal access catheter;inserting a microcatheter into the lumen of the flexible distal luminalelement. The microcatheter includes a lumen; a distal end region havinga distal opening from the lumen; and a side opening from the lumenlocated a distance proximal to the distal opening. A payload is housedwithin the lumen proximal to the side opening. The method furtherincludes advancing the microcatheter through the lumen of the distalaccess catheter until the distal end region of the microcatheter extendsat least to the distal end of the distal access catheter.

The proximal portion of the tapered inner member can be a hypotubehaving an opening in fluid communication with the single lumen of theflexible elongate body. The method can further include inserting asecond distal access catheter through the lumen of the first distalaccess catheter until the second distal access catheter extends distalto the first distal access catheter, wherein inserting the microcatheterinto the lumen of the flexible distal luminal element further includeinserting the microcatheter into the lumen of the second distal accesscatheter.

In an interrelated aspect, disclosed is a rapid exchange microcathetersystem for accessing the intracranial neurovasculature including acatheter body having an outer diameter, an inner diameter, and adistal-most tip, an internal lumen defined by the inner diameter. Thecatheter body is adapted to carry a payload within the internal lumenand deliver the payload from the internal lumen to a target location inthe intracranial neurovasculature. The inner diameter is sized to allowpassage of a guidewire and the outer diameter has a maximum size of lessthan 0.048 inch. A guidewire side opening into the internal lumen issized to allow passage of a guidewire. The guidewire side opening islocated a distance between 10-20 cm from the distal-most tip of thecatheter body. A proximal opening into the internal lumen that isdifferent and distinct from the guidewire side opening is located adistance greater than 20 cm from the distal-most tip. A distal,reinforced catheter portion extends between a distal end region of thecatheter body to a point near the guidewire side opening. A proximal,reinforced catheter portion extends a distance from a point near theguidewire side opening towards the proximal end of the catheter body.The guidewire side opening is positioned within a gap between a proximalend of the distal reinforced catheter portion and a distal end of theproximal, reinforced catheter portion. The system includes instructionsfor use that instruct that the payload be loaded in the internal lumenat a location proximal to the guidewire side opening prior to use of thecatheter body.

In an interrelated aspect, disclosed is a rapid exchange microcathetersystem for accessing the intracranial neurovasculature including acatheter body having an outer diameter, an inner diameter, and adistal-most tip. An internal lumen is defined by the inner diameter. Thecatheter body is adapted to carry a payload within the internal lumenand deliver the payload from the internal lumen to a target location inthe intracranial neurovasculature. The inner diameter is sized to allowpassage of a guidewire and the outer diameter body has a maximum size ofless than 0.048 inch. A guidewire side opening into the internal lumensized to allow passage of a guidewire is located a distance between10-20 cm from the distal-most tip of the catheter body. A proximalopening into the internal lumen that is different and distinct from theguidewire side opening is located a distance greater than 20 cm from thedistal-most tip. A distal, reinforced catheter portion extends between adistal end region of the catheter body to a point near the guidewireside opening. A proximal, reinforced catheter portion extends a distancefrom a point near the guidewire side opening towards the proximal end ofthe catheter body. The guidewire side opening is positioned within a gapbetween a proximal end of the distal reinforced catheter portion and adistal end of the proximal, reinforced catheter portion. The payload isloaded in the internal lumen at a location proximal to the guidewireside opening such that the payload can be carried within and deliveredfrom the internal lumen to a target location in the intracranialneurovasculature.

In some variations, one or more of the following can optionally beincluded in any feasible combination in the above methods, apparatus,devices, and systems. More details of the devices, systems, apparatus,and methods are set forth in the accompanying drawings and thedescription below. Other features and advantages will be apparent fromthe description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects will now be described in detail with referenceto the following drawings. Generally speaking the figures are not toscale in absolute terms or comparatively, but are intended to beillustrative. Also, relative placement of features and elements may bemodified for the purpose of illustrative clarity.

FIGS. 1A-1B illustrate the course of the terminal internal carotidartery through to the cerebral vasculature;

FIG. 2A is an exploded view of an implementation of a single operatordelivery system including a distal access system and a working devicedelivery system;

FIG. 2B is an assembled view of the distal access system of FIG. 2A;

FIG. 2C is an assembled view of the working device delivery systemextending through the distal access system of FIG. 2A;

FIG. 2D illustrates an implementation of an arterial access devicehaving a distal occlusion balloon;

FIG. 3 is a side view of an implementation of a spined distal accesscatheter;

FIG. 4A is a cross-sectional view of first implementation of a proximalcontrol element of a spined distal access catheter;

FIG. 4B is a cross-sectional view of another implementation of aproximal control element of a spined distal access catheter;

FIG. 4C is a cross-sectional view of the proximal control element ofFIG. 4A within a working lumen of an access sheath;

FIG. 4D is a cross-sectional view of the proximal control element ofFIG. 4B within a working lumen of an access sheath having a catheteradvancement element extending therethrough;

FIG. 4E is a cross-sectional, schematic view comparing the surface areaof the proximal control element of FIG. 4A and the proximal controlelement of FIG. 4B within the working lumen of an access sheath of FIG.4D;

FIG. 5A is a side elevational view of an implementation of a spineddistal access catheter;

FIG. 5B is a top plan view of the spined distal access catheter of FIG.5A;

FIG. 5C is a cross-sectional view of the spined distal access cathetertaken along line C-C of FIG. 5B;

FIG. 5D is a cross-sectional view of the spined distal access cathetertaken along line D-D of FIG. 5B;

FIGS. 5E-5F are partial perspective views of the spined distal accesscatheter of FIG. 5A;

FIG. 6A is a side elevational view of an implementation of a spineddistal access catheter;

FIG. 6B is a top plan view of the spined distal access catheter of FIG.6A;

FIG. 6C is a cross-sectional view of the spined distal access cathetertaken along line C-C of FIG. 6B;

FIG. 6D is a cross-sectional view of the spined distal access cathetertaken along line D-D of FIG. 6B;

FIGS. 6E-6F are partial perspective views of the spined distal accesscatheter of FIG. 6A;

FIG. 7A is a side view of an implementation of a catheter advancementelement;

FIG. 7B is a cross-sectional view of the catheter advancement element ofFIG. 7A;

FIG. 7C is a detail view of FIG. 7B taken along circle C-C;

FIG. 7D is a side view of another implementation of a catheteradvancement element;

FIG. 7E is cross-sectional view of an implementation of a proximalportion the catheter advancement element of FIG. 7D;

FIGS. 7F-7J are various views of an implementation of a proximal hub forcoupling to the proximal portion shown in FIG. 7E;

FIGS. 8A-8C illustrate various implementations of single operatorworking device delivery systems configured to be delivered through adistal access system;

FIGS. 9A-9I illustrate an implementation of a method of delivering astent retriever using a single operator delivery system through a distalaccess system;

FIGS. 10A-10H illustrate an implementation of a method using adual-headed rotating hemostatic valve;

FIGS. 11A-11B illustrate the flexibility of the distal access catheterpassing through the cervical carotid and beyond the guide sheathproviding a conduit for insertion of less flexible components into thecervical ICA and beyond;

FIGS. 12A-12B illustrate implementations of single operator workingdevice delivery systems in a side-by-side arrangement with a proceduralguidewire;

FIGS. 13A-13B illustrate implementations of single operator workingdevice delivery systems in a coaxial arrangement with a proceduralguidewire;

FIGS. 14A-14B illustrate implementations of single operator workingdevice delivery systems having a microcatheter with a step-up in outerdiameter;

FIG. 15A illustrates a schematic view of an implementation of a rapidexchange microcatheter for delivering a working device to theneurovasculature for the treatment of stroke;

FIG. 15B is a cross-sectional view of the microcatheter of FIG. 15Ataken along line B-B;

FIG. 15C is a cross-sectional view of the microcatheter of FIG. 15Ataken along line C-C;

FIG. 15D is a cross-sectional view of the microcatheter of FIG. 15Ataken along line D-D;

FIG. 15E is a detail view of the microcatheter of FIG. 15A taken atcircle E-E;

FIGS. 16A-16C illustrate top-down partial views of implementations of arapid exchange microcatheter for delivering a working device to theneurovasculature for the treatment of stroke;

FIGS. 17A-17D illustrate top, side, and cross-sectional views of animplementation of a coupler for the microcatheter of FIGS. 16A-16C;

FIGS. 18A-18C illustrate top, side, and cross-sectional views of animplementation of a coupler for the microcatheter of FIG. 16A-16C;

FIGS. 19A-19C illustrate top, side, and cross-sectional views of animplementation of a coupler for the microcatheter of FIG. 16A-16C;

FIG. 20 illustrates an implementation of a coupler for the microcatheterof FIG. 16A-16C;

FIG. 21 illustrates an implementation of a nested catheter system.

It should be appreciated that the drawings are for example only and arenot meant to be to scale. It is to be understood that devices describedherein may include features not necessarily depicted in each figure.

DETAILED DESCRIPTION

Navigating the carotid anatomy in order to treat various neurovascularpathologies at the level of the cerebral arteries, such as acuteischemic stroke (AIS), requires catheter systems having superiorflexibility and deliverability. The internal carotid artery (ICA) arisesfrom the bifurcation of the common carotid artery (CCA) at the level ofthe intervertebral disc between C3 and C4 vertebrae. As shown in FIG.1A, the course of the ICA is divided into four parts—cervical Cr,petrous Pt, cavernous Cv and cerebral Cb parts. In the anteriorcirculation, the consistent tortuous terminal carotid is locked into itsposition by bony elements. The cervical carotid Cr enters the petrousbone and is locked into a set of turns as it is encased in bone. Thecavernous carotid is an artery that passes through a venous bed, thecavernous sinus, and while flexible, is locked as it exits the cavernoussinus by another bony element, which surrounds and fixes the entry intothe cranial cavity. Because of these bony points of fixation, thepetrous carotid Pt and above are relatively consistent in theirtortuosity. The carotid siphon CS is an S-shaped part of the terminalICA. The carotid siphon CS begins at the posterior bend of the cavernousICA and ends at the ICA bifurcation into the anterior cerebral arteryACA and middle cerebral artery MCA. The ophthalmic artery arises fromthe cerebral ICA, which represents a common point of catheter hang up inaccessing the anterior circulation. These points of catheter hang up cansignificantly increase the amount of time needed to restore bloodperfusion to the brain, which in the treatment of AIS is a disadvantagewith severe consequences.

With advancing age, the large vessels often enlarge and lengthen. Fixedproximally and distally, the carotid often becomes tortuous. The commoncarotid artery CCA is relatively fixed in the thoracic cavity as itexits into the cervical area by the clavicle. The external and internalcarotid arteries ECA, ICA are not fixed relative to the common carotidartery CCA, and thus they develop tortuosity with advancing age withlengthening of the entire carotid system. This can cause them toelongate and develop kinks and tortuosity or, in worst case, a completeloop or so-called “cervical loop”. If catheters used to cross thesekinked or curved areas are too stiff or inflexible, these areas canundergo a straightening that can cause the vessel to wrap around or“barbershop pole” causing focused kinking and folding of the vessel.These sorts of extreme tortuosity also can significantly increase theamount of time needed to restore blood perfusion to the brain,particularly in the aging population. In certain circumstances, thetwisting of vessels upon themselves or if the untwisted artery iskinked, normal antegrade flow may be reduced to a standstill creatingischemia. Managing the unkinking or unlooping the vessels such as thecervical ICA can also increase the time it takes to perform a procedure.

A major drawback of current catheter systems for stroke interventionprocedures is the amount of time required to restore blood perfusion tothe brain, including the time it takes to access the occlusive site orsites in the cerebral artery and the time it takes to completely removethe occlusion in the artery. Because it is often the case that more thanone attempt must be made to completely remove the occlusion, reducingthe number of attempts as well as reducing the time required to exchangedevices for additional attempts is an important factor in minimizing theoverall time. Additionally, each attempt is associated with potentialprocedural risk due to device advancement in the delicate cerebralvasculature. Another limitation is the need for multiple operators todeliver and effectively manipulate long tri-axial systems typically usedwith conventional guide and distal access catheters.

Described herein are catheter systems for treating various neurovascularpathologies, such as acute ischemic stroke (AIS). The systems describedherein provide quick and simple single-operator access to distal targetanatomy, in particular tortuous anatomy of the cerebral vasculature. Themedical methods, devices and systems described herein allow fornavigating complex, tortuous anatomy to perform rapid and safe deliveryof intracranial medical devices, with or without aspiration for theremoval of cerebral occlusions in the treatment of acute ischemicstroke. The systems described herein can be particularly useful for thetreatment of AIS whether a user intends to perform stent retrieverdelivery alone, aspiration alone, or a combination of aspiration andstent retriever delivery as a frontline treatment for AIS. Further, theextreme flexibility and deliverability of the distal access cathetersystems described herein allow the catheters to take the shape of thetortuous anatomy rather than exert straightening forces creating newanatomy. The distal access catheter systems described herein can passthrough tortuous loops while maintaining the natural curves of theanatomy therein decreasing the risk of vessel straightening. The distalaccess catheter systems described herein can thereby create a safeconduit through the neurovasculature maintaining the natural tortuosityof the anatomy for other catheters to traverse (e.g. interventionaldevice delivery catheters). The catheters traversing the conduit neednot have the same degree of flexibility and deliverability such that ifthey were delivered directly to the same anatomy rather than through theconduit, would lead to straightening, kinking, or folding of theanterior circulation.

It should be appreciated that while some implementations are describedherein with specific regard to accessing a neurovascular anatomy ordelivery of an expandable cerebral treatment device, the systems andmethods described herein should not be limited to this and may also beapplicable to other uses. For example, the catheter systems describedherein may be used to deliver working devices to a target vessel of acoronary anatomy or other vasculature anatomy. It should also beappreciated that where the phrase “aspiration catheter” is used hereinthat such a catheter may be used for other purposes besides or inaddition to aspiration, such as the delivery of fluids to a treatmentsite or as a support catheter or distal access catheter providing aconduit that facilitates and guides the delivery or exchange of otherdevices such as a guidewire or interventional devices such as stentretrievers. Alternatively, the access systems described herein may alsobe useful for access to other parts of the body outside the vasculature.Similarly, where the working device is described as being an expandablecerebral treatment device, stent retriever or self-expanding stent otherinterventional devices can be delivered using the delivery systemsdescribed herein.

Referring now to the drawings, FIGS. 2A-2B illustrate a system 10including devices for accessing and removing a cerebral occlusion totreat acute ischemic stroke from an access site. The system 10 can be asingle operator system such that each of the components and systems canbe delivered and used together by one operator using minimal handmovements. As will be described in more detail below, all wire andcatheter manipulations can occur at or in close proximity to a singlerotating hemostatic valve (RHV) 434 or more than a single RHV co-locatedin the same device. The system 10 can include a distal access system 100and an intracranial delivery system 700 each of which will be describedin more detail below. The distal access system 100 can include acatheter 200 configured to be received through a guide sheath 400, thecatheter 200 designed to have exceptional deliverability. The catheter200 can be a spined, distal access catheter co-axial with a lumen of theguide sheath 400 thereby providing a step-up in inner diameter withinthe conduit. The catheter 200 can be delivered using a catheteradvancement element 300 inserted through a lumen 223 of the catheter 200forming a catheter delivery system 150. The intracranial delivery system700 can include a cerebral treatment device or working device 500 fortreatment of the cerebral occlusion. The working device 500 can have adistal expanding payload 505 and a proximal control element 510. Thepayload 505 is configured to be housed within an introducer sheath ormicrocatheter 600. The intracranial delivery system 700 can furtherinclude a procedural guidewire 805.

The distal access system 100 can create a variable length from point ofentry at the percutaneous arteriotomy (e.g. the femoral artery) to thetarget control point of the distal catheter. Conventional distal accesssystems for stroke intervention typically include a long guide sheath orguide catheter placed through a shorter “introducer” sheath (e.g. 11-30cm in length) at the groin. The long guide sheath is typicallypositioned in the ICA to support neurovascular interventions includingstroke thrombectomy. For added support, these can be advanced up to thebony terminal petrous and rarely into the cavernous or clinoid orsupraclinoid terminal ICA when possible. To reach targets in the M1 orM2 distribution for ADAPT/MAT or Solumbra/SMAT approaches, an additionalcatheter is inserted through the long guide catheter. These cathetersare typically large-bore aspiration catheters that can be 130 cm inlength or longer. As will be described in more detail below, the distalaccess systems 100 described herein can be shorter, for example, only115 cm in length, allowing for a shorter intracranial working devicedelivery system 700 to be used with the distal access system 100providing an ease of use advantage more suitable for a single operator.Additionally, the single operator can use the systems described hereinby inserting them through a single rotating hemostatic valve (RHV) 434on the guide sheath 400 or more than one RHV co-located in the samedevice such as a dual-headed RHV. Thus, what was once a two-personprocedure can be a one-person procedure.

Each of the various components of the various systems will now bedescribed in more detail.

Distal Access System

Again with respect to FIGS. 2A-2D (as well as FIGS. 8A-8C, 9A-9I, and10A-10H), the distal access system 100 can include an access guidesheath 400 having a body 402 through which a working lumen 410 extendsfrom a proximal hemostasis valve 434 coupled to a proximal end region403 of the body 402 to a distal opening 408 of a distal end region. Theworking lumen 410 is configured to receive the support catheter 200 ofthe distal access system 100 therethrough such that a distal end of thecatheter 200 extends beyond a distal end of the sheath 400 through thedistal opening 408. The guide sheath 400 can be used to deliver thecatheters described herein as well as any of a variety of workingdevices known in the art. For example, the working devices can beconfigured to provide thrombotic treatments and can include large-borecatheters, aspiration thrombectomy, advanced catheters, wires, balloons,retrievable structures such as coil-tipped retrievable stents“Stentriever”. The guide sheath 400 in combination with the supportcatheter 200 can also be used to apply distal aspiration as will bedescribed in more detail below.

The guide sheath 400 can be any of a variety of commercially availableguide sheaths. For example, the guide sheath 400 can have an internaldiameter (ID) between 0.087″-0.089″ such as the Cook SHUTTLE 6 F (CookMedical, Inc., Bloomington, Ind.), Terumo DESTINATION 6 F (Terumo EuropeNV), Cordis VISTA BRITE TIP (Cordis Corp., Hialeah, Fla.), and PenumbraNEURON MAX 088 (Penumbra, Inc., Alameda, Calif.), or comparablecommercially available guiding sheath. Generally, sheath sizes aredescribed herein using the French (F) scale. For example, where a sheathis described as being 6 French, it should be appreciated that the innerdiameter of that sheath is able to receive a catheter having a 6 F outerdiameter, which is about 1.98 mm or 0.078″. It should be appreciated,therefore, that a catheter may be described herein as having aparticular size in French to refer to the compatibility of its innerdiameter to receive an outer diameter of another catheter. A cathetermay also be described herein as having a particular size in French torefer to its outer diameter being compatible with another catheterhaving a particular inner diameter.

Again with respect to FIGS. 2A-2D, the elongated body 402 can extendfrom a proximal furcation or rotating hemostatic valve (RHV) 434 at aproximal end region 403 to a tip 406 at a distal end of the body 402.The proximal RHV 434 may include one or more lumens molded into aconnector body to connect to the working lumen 410 of the body 402 ofthe guide sheath 400. As described above, the working lumen 410 canreceive the catheter 200 and/or any of a variety of working devices fordelivery to a target anatomy. The RHV 434 can be constructed ofthick-walled polymer tubing or reinforced polymer tubing. The RHV 434allows for the introduction of devices through the guide sheath 400 intothe vasculature, while preventing or minimizing blood loss andpreventing air introduction into the guide sheath 400. The RHV 434 canbe integral to the guide sheath 400 or the guide sheath 400 canterminate on a proximal end in a female Luer adaptor to which a separatehemostasis valve component, such as a passive seal valve, a Tuohy-Borstvalve or rotating hemostasis valve may be attached. The RHV 434 can havean adjustable opening that is open large enough to allow removal ofdevices that have adherent clot on the tip without causing the clot todislodge at the RHV 434 during removal. Alternately, the RHV 434 can beremovable such as when a device is being removed from the sheath 400 toprevent clot dislodgement at the RHV 434. The RHV 434 can be a dual RHV.

The RHV 434 can form a Y-connector on the proximal end 403 of the sheath400 such that the first port of the RHV 434 can be used for insertion ofa working catheter into the working lumen 410 of the sheath 400 and asecond port into arm 412 can be used for another purpose. For example, asyringe or other device can be connected at arm 412 via a connector 432to deliver a forward drip, a flush line for contrast or salineinjections through the body 402 toward the tip 406 and into the targetanatomy. Arm 412 can also connect to a large-bore aspiration line and anaspiration source (not shown) such as a syringe or pump to draw suctionthrough the working lumen 410. The arm 412 can also allow the guidesheath 400 to be flushed with saline or radiopaque contrast during aprocedure. The working lumen 410 can extend from a distal end to aworking proximal port of the proximal end region 403 of the elongatedbody 402.

The length of the elongated body 402 is configured to allow the distaltip 406 of the body 402 to be positioned as far distal in the internalcarotid artery (ICA), for example, from a transfemoral approach withadditional length providing for adjustments if needed. In someimplementations, the length of the body 402 can be in the range of 80 to90 cm although it should be appreciated that the of the body 402 can belonger, for example, up to about 100 cm or up to about 105 cm. Inimplementations, the body 402 length is suitable for a transcarotidapproach to the bifurcation of the carotid artery, in the range of 20-25cm. In further implementations, the body 402 length is suitable for atranscarotid approach to the CCA or proximal ICA, and is in the range of10-15 cm. The body 402 is configured to assume and navigate the bends ofthe vasculature without kinking, collapsing, or causing vascular trauma,even, for example, when subjected to high aspiration forces.

The tip 406 of the guide sheath 400 can have a same or similar outerdiameter as a section of the body 402 leading up to the distal end.Accordingly, the tip 406 may have a distal face orthogonal to alongitudinal axis passing through the body 402 and the distal face mayhave an outer diameter substantially equal to a cross-sectional outerdimension of the body 402. In an implementation, the tip 406 includes achamfer, fillet, or taper, making the distal face diameter slightly lessthan the cross-sectional dimension of the body 402. In a furtherimplementation, the tip 406 may be an elongated tubular portionextending distal to a region of the body 402 having a uniform outerdiameter such that the elongated tubular portion has a reduced diametercompared to the uniform outer diameter of the body 402. Thus, the tip406 can be elongated or can be more bluntly shaped. Accordingly, the tip406 may be configured to smoothly track through a vasculature and/or todilate vascular restrictions as it tracks through the vasculature. Theworking lumen 410 may have a distal end forming a distal opening 408.

The guide sheath 400 may include a tip 406 that tapers from a section ofthe body 402 leading up to the distal end. That is, an outer surface ofthe body 402 may have a diameter that reduces from a larger dimension toa smaller dimension at a distal end. For example, the tip 406 can taperfrom an outer diameter of approximately 0.114″ to about 0.035″. Theangle of the taper of the tip 406 can vary depending on the length ofthe tapered tip 406. For example, in some implementations, the tip 406tapers from 0.110″ to 0.035″ over a length of approximately 50 mm.

In an implementation, the guide sheath 400 includes one or moreradiopaque markers 411. The radiopaque markers 411 can be disposed nearthe distal tip 406. For example, a pair of radiopaque bands may beswaged, painted, embedded, or otherwise disposed in or on the body 402.In some implementations, the radiopaque markers 411 include a bariumpolymer, tungsten polymer blend, tungsten-filled or platinum-filledmarker that maintains flexibility of the distal end of the device andimproves transition along the length of the guide sheath 400 and itsresistance to kinking. In some implementations, the radiopaque marker411 is a tungsten-loaded PEBAX or polyurethane that is heat welded tothe body 402. The markers 411 are shown in the figures as rings around acircumference of one or more regions of the body 402. However, themarkers 411 can have other shapes or create a variety of patterns thatprovide orientation to an operator regarding the position of the distalopening 408 within the vessel. Accordingly, an operator may visualize alocation of the distal opening 408 under fluoroscopy to confirm that thedistal opening 408 is directed toward a target anatomy where a catheter200 is to be delivered. For example, radiopaque marker(s) 411 allow anoperator to rotate the body 402 of the guide sheath 400 at an anatomicalaccess point, e.g., a groin of a patient, such that the distal openingprovides access to an ICA by subsequent working device(s), e.g.,catheters and wires advanced to the ICA. In some implementations, theradiopaque marker(s) 411 include platinum, gold, tantalum, tungsten orany other substance visible under an x-ray fluoroscope. It should beappreciated that any of the various components of the systems describedherein can incorporate radiopaque markers as described above.

In some implementations, the guide sheath 400 will have performancecharacteristics similar to other sheaths used in carotid access and AISprocedures in terms of kinkability, radiopacity, column strength, andflexibility. The inner liners can be constructed from a low frictionpolymer such as PTFE (polytetrafluoroethylene) or FEP (fluorinatedethylene propylene) to provide a smooth surface for the advancement ofdevices through the inner lumen. An outer jacket material can providemechanical integrity to the inner liners and can be constructed frommaterials such as PEBAX, thermoplastic polyurethane, polyethylene,nylon, or the like. A third layer can be incorporated that can providereinforcement between the inner liner and the outer jacket. Thereinforcement layer can prevent flattening or kinking of the inner lumenof the body 402 to allow unimpeded device navigation through bends inthe vasculature as well as aspiration or reverse flow. The body 402 canbe circumferentially reinforced. The reinforcement layer can be madefrom metal such as stainless steel, Nitinol, Nitinol braid, helicalribbon, helical wire, cut stainless steel, or the like, or stiff polymersuch as PEEK. The reinforcement layer can be a structure such as a coilor braid, or tubing that has been laser-cut or machine-cut so as to beflexible. In another implementation, the reinforcement layer can be acut hypotube such as a Nitinol hypotube or cut rigid polymer, or thelike. The outer jacket of the body 402 can be formed of increasinglysofter materials towards the distal end. For example, proximal region ofthe body 402 can be formed of a material such as Nylon, a region of thebody 402 distal to the proximal region of the body 402 can have ahardness of 72D whereas areas more distal can be increasingly moreflexible and formed of materials having a hardness of 55D, 45D, 35Dextending towards the distal tip 406, which can be formed of a materialhaving a hardness of 35D, for example. The body 402 can include ahydrophilic coating.

The flexibility of the body 402 can vary over its length, withincreasing flexibility towards the distal portion of the body 402. Thevariability in flexibility may be achieved in various ways. For example,the outer jacket may change in durometer and/or material at varioussections. A lower durometer outer jacket material can be used in adistal section of the guide sheath compared to other sections of theguide sheath. Alternately, the wall thickness of the jacket material maybe reduced, and/or the density of the reinforcement layer may be variedto increase the flexibility. For example, the pitch of the coil or braidmay be stretched out, or the cut pattern in the tubing may be varied tobe more flexible. Alternately, the reinforcement structure or thematerials may change over the length of the elongate body 402. Inanother implementation, there is a transition section between thedistal-most flexible section and the proximal section, with one or moresections of varying flexibilities between the distal-most section andthe remainder of the elongate body 402. In this implementation, thedistal-most section is about 2 cm to about 5 cm, the transition sectionis about 2 cm to about 10 cm and the proximal section takes up theremainder of the sheath length.

The different inner diameters of the guide sheaths 400 can be used toreceive different outer diameter catheters 200. In some implementations,the working lumen 410 of a first guide sheath 400 can have an innerdiameter sized to receive a 6 F catheter and the working lumen 410 of asecond guide sheath 400 can have an inner diameter sized to receive a 8F catheter. In some implementations, the distal region of the guidesheath 400 can have an inner diameter of about 0.087″ to 0.088″. Theguide sheaths 400 can receive catheters having an outer diameter that issnug to these inner diameter dimensions. It should be appreciated thatthe guide sheath 400 (as well as any of the variety of components usedin combination with the sheath 400) can be an over-the-wire (OTW) orrapid exchange type device, which will be described in more detailbelow.

In some instances it is desirable for the sheath body 402 to also beable to occlude the artery in which it is positioned, for example,during procedures that may create distal emboli. Occluding the arterystops antegrade blood flow and thereby reduces the risk of distal embolithat may lead to neurologic symptoms such as TIA or stroke. FIG. 2Dshows an arterial access device or sheath 400 that has a distalocclusion balloon 440 that upon inflation occludes the artery at theposition of the sheath distal tip 406. At any point in a procedure, forexample, during removal of an occlusion by aspiration and/or delivery ofa stentriever or other interventional device, the occlusion balloon 440can be inflated to occlude the vessel to reduce the risk of distalemboli to cerebral vessels. The sheath 400 can include an inflationlumen configured to deliver a fluid for inflation of the occlusionballoon 440 in addition to the working lumen of the sheath 400. Theinflation lumen can fluidly connect the balloon 440, for example, to arm412 on the proximal adaptor. This arm 412 can be attached to aninflation device such as a syringe to inflate the balloon 440 with afluid when vascular occlusion is desired. The arm 412 may be connectedto a passive or active aspiration source to further reduce the risk ofdistal emboli.

According to some implementations, the length of the guide sheath 400 islong enough to access the target anatomy and exit the arterial accesssite with extra length outside of a patient's body for adjustments. Forexample, the guide sheath 400 (whether having a distal occlusion balloon440 or not) can be long enough to access the petrous ICA from thefemoral artery such that an extra length is still available foradjustment. The guide sheath 400 can be a variety of sizes to acceptvarious working devices and can be accommodated to the operator'spreference. For example, current MAT and SMAT techniques describedelivering aspiration catheters having inside diameters of 0.054″-0.072″to an embolus during AIS. Accordingly, the working lumen 410 of theguide sheath 400 can be configured to receive the catheter 200 as wellas other catheters or working devices known in the art. For example, theworking lumen 410 can have an inner diameter sized to accommodate atleast 6 French catheters (1.98 mm or 0.078″ OD), or preferably at least6.3 French catheters (2.079 mm or 0.082″ OD). The inner diameter of theguide sheath 400, however, may be smaller or larger to be compatiblewith other catheter sizes. In some implementations, the working lumen410 can have an inner diameter sized to accommodate 7 French (2.31 mm or0.091″ OD) catheters or 8 French (2.64 mm or 0.104″ OD) or largercatheters. In some implementations, the working lumen 410 can have aninner diameter that is at least about 0.054″ up to about 0.070″, 0.071″,0.074″, 0.087″, 0.088″, or 0.100″ and thus, is configured to receive acatheter 200 having an outer diameter that fits snug with thesedimensions. Regardless of the length and inner diameter, the guidesheath 400 is resistant to kinking during distal advancement through thevasculature.

The working lumen 410 included in the sheath 400 can be sized to receiveits respective working devices in a sliding fit. The working lumen 410may have an inner diameter that is at least 0.001 inch larger than anouter diameter of any catheter 200 it is intended to receive,particularly if the catheter 200 is to be used for aspiration as will bedescribed in more detail below. As described in more detail below, thecatheter 200 can include a slit 236 in the luminal portion 222configured to widen slightly upon application of suction from anaspiration source and improve sealing between the catheter 200 and theguide sheath 400. The strength of the seal achieved allows for acontinuous aspiration lumen from the distal tip of the catheter 200 to aproximal end 403 of the guide sheath 400 where it is connected to anaspiration source, even in the presence of lower suction forces withminimal to no leakage. Generally, when there is enough overlap betweenthe catheter 200 and the guide sheath 400 there is no substantialleakage. However, when trying to reach distal anatomy, the catheter 200may be advanced to its limit and the overlap between the catheter 200and the guide sheath 400 is minimal. Thus, additional sealing can bedesirable to prevent leakage around the catheter 200 into the sheath400. The sealing between the catheter 200 and the guide sheath 400 canprevent this leakage upon maximal extension of catheter 200 relative tosheath 400.

Distal Access Catheter

Again with respect to FIGS. 2A-2C and also FIG. 3, the distal accesssystem 100 can include a distal access or support catheter 200configured to extend through and out the distal end of the guide sheath400. FIG. 3 illustrates a side elevational view of an implementation ofthe support catheter 200. The catheter 200 can include a relativelyflexible, distal luminal portion 222 coupled to a more rigid,kink-resistant proximal control element 230. The support catheter 200provides a quick way to access stroke locations with simplicity eventhrough the extreme tortuosity of the cerebral vasculature. The supportcatheters described herein have a degree of flexibility anddeliverability that makes them optimally suitable to be advanced throughthe cerebral vascular anatomy without kinking or ovalizing even whennavigating hairpin turns. For example, the distal luminal portion 222can perform a 180 degree turn (see turn T shown in FIG. 1B near thecarotid siphon) and maintain a folded width across of 4.0 mm withoutkinking or ovalizing. Further, the distal luminal portion 222 has adegree of flexibility that maintains the natural tortuosity of thevessels through which it is advanced without applying straighteningforces such that the natural shape and curvature of the anatomy ismaintained during use. The support catheter 200, particularly incombination with a catheter advancement element 300, which will bedescribed in more detail below, provides an extended conduit beyond theguide sheath 400 having exceptional deliverability through convolutedanatomy that allows for delivering aspirational forces to a targetstroke site as well as for the delivery of stroke interventional devicessuch as a stent retriever, stent, flow diverter or other workingdevices.

An inner lumen 223 extends through the luminal portion 222 between aproximal end and a distal end of the luminal portion 222. The innerlumen 223 of the catheter 200 can have a first inner diameter and theworking lumen 410 of the guide sheath 400 can have a second, largerinner diameter. Upon insertion of the catheter 200 through the workinglumen 410 of the sheath 400, the lumen 223 of the catheter 200 can beconfigured to be fluidly connected and contiguous with the working lumen410 of the sheath 400 such that fluid flow into and/or out of the system100 is possible, such as by applying suction from an aspiration sourcecoupled to the system 100 at a proximal end. The combination of sheath400 and catheter 200 can be continuously in communication with thebloodstream during aspiration at the proximal end with advancement andwithdrawal of catheter 200.

The spined catheter system can create advantages for distal access overconventional catheters particularly in terms of aspiration. The stepchange in the internal diameter of the catheter column creates a greatadvantage in aspiration flow and force that can be generated by thespined catheter 200 in combination with the conventional guide catheter.For example, where a spined catheter 200 with a 0.070″ internal diameteris paired with a standard 6 F outer diameter/0.088″ internal diameterguide catheter (e.g. Penumbra Neuron MAX 088) can create aspirationphysics where the 0.088″ catheter diameter will predominate and create a0.080 equivalent flow in the entire system.

In addition to aspiration procedures, the support catheter 200 anddistal access system 100 can be used for delivery of tools andinterventional working devices. As will be described in more detailbelow, a typical stent retriever to be delivered through the supportcatheter 200 can have a push wire control element of 180 cm. The distalaccess system 100 having a spined support catheter 200 allows forreaching distal stroke sites using much shorter lengths (e.g. 120 cm-150cm). The overall length can be as important as diameter and radius onaspiration through the catheter. The shorter lengths in combination withthe elimination of the multiple RHVs typical in tri-axial systems allowsfor a single-operator use.

It should be appreciated that where the distal access catheter isdescribed herein as an aspiration catheter it should not be limited toonly aspiration. Similarly, where the catheter is described herein as away to deliver a stent retriever or other working device 500 it shouldnot be limited as such. It should also be appreciated that the systemsdescribed herein can be used to perform procedures that incorporate acombination of treatments. For example, the support catheter 200 can beused for the delivery of a stent retriever delivery system, optionallyin the presence of aspiration through the support catheter 200. Asanother example, a user may start out performing a first interventionalprocedure using the systems described herein, such as aspirationthrombectomy, and switch to another interventional procedure, such asdelivery of a stent retriever or implant.

It should also be appreciated that the catheter 200 need not be spinedor include the proximal control element 230 and instead can be anon-spined, conventional catheter having a uniform diameter. The terms“support catheter”, “spined catheter”, “distal access catheter”, and“intermediate catheter” may be used interchangeably herein.

It is desirable to have a catheter 200 having an inner diameter that isas large as possible that can be navigated safely to the site of theocclusion, in order to optimize the aspiration force in the case ofaspiration and/or provide ample clearance for delivery of a workingdevice. A suitable size for the inner diameter of the distal luminalportion 222 may range between 0.040″ and 0.100″, depending on thepatient anatomy and the clot size and composition. The outer diameter ofthe distal luminal portion 222 can be sized for navigation into cerebralarteries, for example, at the level of the M1 segment or M2 segment ofthe cerebral vessels. The outer diameter (OD) should be as small aspossible while still maintaining the mechanical integrity of thecatheter 200. In an implementation, the difference between the OD ofdistal luminal portion 222 of the catheter 200 and the inner diameter ofthe working lumen 410 of the guide sheath 400 is between 0.001″ and0.002″. In another implementation, the difference is between 0.001″ and0.004″.

In some implementations, the distal luminal portion 222 of the catheter200 has an outer diameter (OD) configured to fit through a 6 Fintroducer sheath (0.071″) and the lumen 223 has an inner diameter (ID)that is sized to receive a 0.054″ catheter. In some implementations, thedistal luminal portion 222 of the catheter 200 has an OD configured tofit through an 8 F introducer sheath (0.088″) and the lumen 223 has anID that is sized to receive a 0.070″ or 0.071″ catheter. In someimplementations, the OD of the distal luminal portion 222 is 2.1 mm andthe lumen 223 has an ID that is 0.071″. In some implementations, thelumen 223 has an ID that is 0.070″ to 0.073″. The outer diameter of theguide sheath 400 can be suitable for insertion into at least the carotidartery, with a working lumen 410 suitably sized for providing apassageway for the catheter 200 to treat an occlusion distal to thecarotid artery towards the brain. In some implementations, the ID of theworking lumen 410 can be about 0.074″ and the OD of the body of theguide sheath 400 can be about 0.090″, corresponding to a 5 French sheathsize. In some implementations, the ID of the working lumen 410 can beabout 0.087″ and the OD of the body of the guide sheath 400 can be about0.104″, corresponding to a 6 French sheath size. In someimplementations, the ID of the working lumen 410 can be about 0.100″ andthe OD of the body of the guide sheath 400 can be about 0.117″,corresponding to a 7 French sheath size. In some implementations, theguide sheath 400 ID is between 0.087″ and 0.088″ and the OD of thedistal luminal portion 222 of the catheter 200 is approximately 0.082″and 0.086″ such that the difference in diameters is between 0.001″ and0.005″.

In an implementation, the luminal portion 222 of the catheter 200 has auniform diameter from a proximal end to a distal end. In otherimplementations, the luminal portion 222 of the catheter 200 is taperedand/or has a step-down towards the distal end of the distal luminalportion 222 such that the distal-most end of the catheter 200 has asmaller outer diameter compared to a more proximal region of thecatheter 200, for example near where the distal luminal portion 222seals with the guide sheath 400. In another implementation, the luminalportion 222 of the catheter OD steps up at or near an overlap portion tomore closely match the sheath inner diameter as will be described inmore detail below. This implementation is especially useful in a systemwith more than one catheter suitable for use with a single access sheathsize. It should be appreciated that smaller or larger sheath sizes areconsidered herein.

The length of the luminal portion 222 can be shorter than a length ofthe working lumen 410 of the guide sheath 400 such that upon advancementof the luminal portion 222 towards the target location results in ashort overlap region 348 between the luminal portion 222 and the workinglumen 410 remains (see FIGS. 2B-2C). Taking into account the variationin occlusion sites and sites where the guide sheath 400 distal tip 406may be positioned, the length of the luminal portion 222 may range fromabout 10 cm to about 40 cm. In some implementations, the distal luminalportion 222 of the catheter 200 can be between 20-40 cm and the controlelement 230 of the catheter 200 can be between about 90-100 cm such thatthe catheter 200 can have a total working length that is approximately115 cm. The body 402 of the guide sheath 400 can be between 80-90 cm. Inother implementations, the working length of the catheter 200 between aproximal end of the catheter to a distal end of the catheter can begreater than 115 cm up to about 130 cm. In some implementations, thecatheter 200 can have a working length of 133 cm between a proximal tab234 (or proximal hub) and the distal tip, the distal luminal portion 222can have a shaft length of about 38.7 mm.

The length of the luminal portion 222 can be less than the length of thebody 402 of the guide sheath 400 such that as the catheter 200 isextended from the working lumen 410 there remains a seal between theoverlap region 348 of the catheter 200 and the inner diameter of theworking lumen 410. In some implementations, the length of the luminalportion 222 is sufficient to reach a region of the M1 segment of themiddle cerebral artery (MCA) and other major vessels from a region ofthe internal carotid artery such that the proximal end region of theluminal portion 222 of the catheter 200 avoids extending within theaortic arch. This limits the number of severe angulations the luminalportion 222 of the catheter 200 must navigate while still reachingtarget sites in the more distal cerebral anatomy. Used in conjunctionwith a guide sheath 400 having a sheath body 402 and a working lumen410, in an implementation where the catheter 200 reaches the ICA and thedistance to embolus can be less than 20 cm.

The distal luminal portion 222 having a length of approximately 25 cmcan allow for an overlap region 348 with the body 402 to create a seal.The overlap region 348 can be maintained between the working lumen 410of the guide sheath 400 near a distal end region of the sheath body 402and the luminal portion 222 of the catheter 200 upon extension of theluminal portion 222 into the target anatomy. It should be appreciatedwhere the OD of the catheter 200 along at least a portion of the distalluminal portion 222 substantially matches the inner diameter of theguide sheath 400 or the difference can be between 0.001″-0.002″, a sealto fluid being injected or aspirated can be achieved by the overlapregion 348. The difference between the catheter OD and the innerdiameter of the guide sheath 400 can vary, for example, between 1-2thousandths of an inch, or between 1-4 thousandths of an inch, orbetween 1-12 thousandths of an inch. A seal to fluid being injected oraspirated between the catheter and the sheath can be achieved by theoverlap 348 between their substantially similar dimensions withoutincorporating any separate sealing structure or seal feature.

The overlap region 348 can have a length of a few centimeters and mayvary depending on the distance from the embolus to the distal end of thedistal luminal portion 222, e.g., depending on how far the catheter 200is advanced relative to the guide sheath 400. The overlap region 348 issized and configured to create a seal that allows for a continuousaspiration lumen from the distal tip region of the catheter 200 to aproximal end region 403 of the guide sheath 400 where it can beconnected to an aspiration source. The strength of the seal achieved canbe a function of the difference between the outer diameter of thecatheter 200 and the inner diameter of the working lumen 410 as well asthe length of the overlap region 348, the force of the suction applied,and the materials of the components. For example, the sealing can beimproved by increasing the length of the overlap region 348. However,increasing the length of the overlap region 348 can result in a greaterlength through which aspiration is pulled through the smaller diameterof the luminal portion 222 rather than the larger diameter of theworking lumen 410. As another example, higher suction forces applied bythe aspiration source can create a stronger seal between the luminalportion 222 and the working lumen 410 even in the presence of a shorteroverlap region 348. Further, a relatively softer material forming theluminal portion and/or the body 402 can still provide a sufficient sealeven if the suction forces are less and the overlap region 348 isshorter. In an implementation, the overlap region 348 is configured toenable sealing against a vacuum of up to 28 inHg. In an implementation,the overlap region 348 is configured to enable sealing against apressure of up to 300 mmHg or up to 600 mmHg or up to 700 mmHg withminimal to no leakage.

It should be appreciated that sealing at the overlap region can be dueto the small difference in inner and outer diameters and/or can be dueto an additional sealing element positioned on an external surface ofthe distal luminal portion or an inner surface of the sheath body. Asealing element can include a stepped up diameter or protruding featurein the overlap region. The sealing element can include one or moreexternal ridge features. The one or more ridge features can becompressible when the luminal portion is inserted into the lumen of thesheath body. The ridge geometry can be such that the sealing elementbehaves as an O-ring, quad ring, or other piston seal design. Thesealing element can include one or more inclined surfaces biased againstan inner surface of the sheath body lumen. The sealing element caninclude one or more expandable members actuated to seal. The inflatableor expandable member can be a balloon or covered braid structure thatcan be inflated or expanded and provide sealing between the two devicesat any time, including after the catheter is positioned at the desiredsite. Thus, no sealing force need be exerted on the catheter duringpositioning, but rather applied or actuated to seal after the catheteris positioned. The sealing element can be positioned on the externalsurface of the distal luminal portion, for example, near the proximalend region of the distal luminal portion and may be located within theoverlap region. More than a single sealing element can be positioned ona length of the catheter.

In some implementations, the additional sealing element can be a cupseal, a balloon seal, or a disc seal formed of a soft polymer positionedaround the exterior of the distal luminal portion near the overlapregion to provide additional sealing. The sealing element can be athin-wall tubing with an outer diameter that substantially matches theinner diameter of the sheath body lumen. The tubing can be sealed on oneend to create a cup seal or on both ends to create a disc or balloonseal. The balloon seal can include trapped air that creates acollapsible space. One or more slits can be formed through the walltubing such that the balloon seal can be collapsible and more easilypassed through an RHV. The balloon seal need not include slits for aless collapsible sealing element that maintains the trapped air. Thesealing element can be tunable for sheath fit and collapse achieved.

Again with respect to FIG. 3, the proximal control element 230 isconfigured to move the distal luminal portion 222 in a bidirectionalmanner through the working lumen 410 of the guide sheath 400 such thatthe distal luminal portion 222 can be advanced out of the guide sheath400 into a target location for treatment within the target vessel. Insome implementations and as shown in FIG. 3, the proximal controlelement 230 of the catheter 200 can have a smaller outer diameter thanthe outer diameter of the distal luminal portion 222 forming a proximalspine or tether to the catheter 200. A smaller outer diameter for theproximal control element 230 than the outer diameter of the distalluminal portion 222 allows for the larger diameter working lumen 410 ofthe sheath 400 to maintain greater aspiration forces than wouldotherwise be provided by the smaller diameter luminal portion 222 of thecatheter 200 or allow for the delivery of working devices through thelumen with less frictional forces. The markedly shorter length of theluminal portion 222 results in a step-up in luminal diameter between theluminal portion 222 contiguous with the working lumen 410 providing amarkedly increased radius and luminal area for delivery of a workingdevice and/or aspiration of the clot, particularly in comparison toother systems where the aspiration lumen runs along the entire innerdiameter of the aspiration catheter. More particularly, the combinedvolume of the luminal area of the catheter 200 and the luminal area ofthe working lumen 410 proximal to the distal luminal portion 222 isgreater than the luminal area of the large bore catheter along theentire length of the system. Thus, the likelihood of removing theembolus during a single aspiration attempt may be increased. Moreparticularly, the stepped up luminal diameter along the proximal controlelement 230 may enable a greater aspiration force to be achievedresulting in improved aspiration of the embolus. Further, thisconfiguration of the catheter 200 and proximal control element 230greatly speeds up the time required to retract and re-advance thecatheter 200 and/or working devices 500 through the working lumen 410out the distal lumen 408. The proximal control element 230 of thecatheter 200 has a length and structure that extends through the workinglumen 410 of the sheath-guide 400 to a proximal end of the system 100such that the proximal control element 230 can be used to advance andretract the catheter 200 through the working lumen 410. The proximalcontrol element 230 of the catheter 200, however, takes up only afraction of the luminal space of the system 100 resulting in increasedluminal area for aspiration and/or delivery of working devices. Thestepped up luminal diameter also increases the annular area availablefor forward flushing of contrast, saline, or other solutions whiledevices such as microcatheters or other devices may be coaxiallypositioned in the luminal portion 222 of the catheter 200 and/or theworking lumen 410. This can increase the ease and ability to performangiograms during device navigation.

In an implementation, the distal luminal portion 222 of the catheter 200is constructed to be flexible and lubricious, so as to be able to safelynavigate to the target location. The distal luminal portion 222 can bekink resistant and collapse resistant when subjected to high aspirationforces so as to be able to effectively aspirate a clot. The luminalportion 222 can have increasing flexibility towards the distal end withsmooth material transitions along its length to prevent any kinks,angulations or sharp bends in its structure, for example, duringnavigation of severe angulations such as those having 90° or greater to180° turns, for example at the aorto-iliac junction, the left subclaviantake-off from the aorta, the takeoff of the brachiocephalic (innominate)artery from the ascending aorta and many other peripheral locations justas in the carotid siphon. For example, a first portion of the distalluminal portion 222 can be formed of a material having a hardness of 72Dalong a first length, a second portion can be formed of a materialhaving a hardness of 55D along a second length, a third portion can beformed of a material such as Pebax MX1205 (40D) along a third length, afourth portion can be formed of a material having a hardness of 35Dalong a fourth length, a fifth portion can be formed of a materialhaving a hardness of 25D along a fifth length, a sixth portion can beformed of a material such as Tecoflex having a hardness of 85A along asixth length, and a final distal portion of the catheter can be formedof a material such as Tecoflex having a hardness of 80A. Thus, thedistal luminal portion 222 transition from being less flexible near itsjunction with the proximal control element 230 to being more flexible atthe distal-most end where, for example, a distal tip of the catheteradvancement element 300 can extend from. It should be appreciated thatother procedural catheters described herein can have a similarconstruction providing a variable relative stiffness that transitionsfrom the proximal end towards the distal end of the catheter as will bedescribed elsewhere herein.

In some implementations, the distal luminal portion 222 can transitionfrom being less flexible near its junction with the proximal controlelement 230 to being more flexible at the distal-most end. The change inflexibility from proximal to distal end of the distal luminal portion222 can be achieved by any of a variety of methods as described herein.In some implementations, the distal luminal portion 222 has areinforcement structure that is a nitinol ribbon wrapped into a coil.The coil can be heat-set prior to transferring the coil onto thecatheter. The pitch of the coil can increase from proximal end towardsdistal end of the distal luminal portion 222. For example, the ribboncoils can have gaps in between them and the size of the gaps canincrease moving towards the distal end of the distal luminal portion222. For example, the size of the gap between the ribbon coils can beapproximately 0.016″ gap near the proximal end of the distal luminalportion 222 and the size of the gap between the ribbon coils near thedistal end can be larger such as 0.036″ gap. This change in pitchprovides for increasing flexibility near the distal-most end of thedistal luminal portion 222.

In an implementation, the distal-most end of the distal luminal portion222 has a flexural stiffness (E*I) in the range of 1500 to 3000 N-mm²and the remaining portion of the distal luminal portion 222 has a higherflexural stiffness, where E is the elastic modulus and I is the areamoment of inertia of the device. These bending stiffness ranges in N-mm²can be measured by assessing the grams of force generated upondeflecting the device a certain distance using a particular lengthgauge. For example, using a 3 mm length force gauge and deflecting a tipof the catheter 2 mm, 30-60 grams of force can be generated or can rangein bending stiffness between 1500-3000 N-mm². The flexibility of thedistal luminal portion 222 can be based on deflection measurements andthe related calculations. As a comparison, the flexibility of thecatheter advancement element 300 based on similar deflectionmeasurements and calculations can be as follows. Upon 2 mm deflectionand force gauge length of 3 mm, the catheter advancement element 300 canrange in gram-force between 1-5 or can range in bending stiffnessbetween 50-200 N-mm². It should be appreciated that other proceduralcatheters described herein can have a similar flexibility rangesproviding a variable relative stiffness that transitions from theproximal end towards the distal end of the catheter as will be describedelsewhere herein.

In some implementations, the distal luminal portion 222 includes two ormore layers. In some implementations, the distal luminal portion 222includes an inner lubricious liner, a reinforcement layer, and an outerjacket layer. The outer jacket layer may be composed of discreetsections of polymer with different durometers, composition, and/orthickness to vary the flexibility along the length of the distal luminalportion 222. In an implementation, the lubricious inner liner is a PTFEliner, with one or more thicknesses along variable sections offlexibility. In an implementation, the reinforcement layer is agenerally tubular structure formed of, for example, a wound ribbon orwire coil or braid. The material for the reinforcement structure may bestainless steel, for example 304 stainless steel, nitinol, cobaltchromium alloy, or other metal alloy that provides the desiredcombination of strengths, flexibility, and resistance to crush. In animplementation, the reinforcement structure includes multiple materialsand/or designs, again to vary the flexibility along the length of thedistal luminal portion 222. In an implementation, the outer surface ofthe catheter 200 is coated with a lubricious coating such as ahydrophilic coating. In some implementations the coating may be on aninner surface and/or an outer surface to reduce friction duringtracking. The coating may include a variety of materials as is known inthe art. The proximal control element 230 may also be coated to improvetracking through the working lumen 410. Suitable lubricious polymers arewell known in the art and may include silicone and the like, hydrophilicpolymers such as high-density polyethylene (HDPE),polytetrafluoroethylene (PTFE), polyarylene oxides,polyvinylpyrolidones, polyvinylalcohols, hydroxy alkyl cellulosics,algins, saccharides, caprolactones, and the like, and mixtures andcombinations thereof. Hydrophilic polymers may be blended amongthemselves or with formulated amounts of water insoluble compounds(including some polymers) to yield coatings with suitable lubricity,bonding, and solubility.

Again with respect to FIGS. 2A-2C, the distal luminal portion 222 of thecatheter 200 can have a radiopaque marker 224 a at the distal tip regionto aid in navigation and proper positioning of the tip underfluoroscopy. Additionally, a proximal region of the catheter 200 mayhave one or more proximal radiopaque markers 224 b so that the overlapregion 348 can be visualized as the relationship between a radiopaquemarker 411 on the guide sheath 400 and the radiopaque marker 224 b onthe catheter 200. In an implementation, the two radiopaque markers(marker 224 a at distal tip and a more proximal marker 224 b) aredistinct so as to minimize confusion of the fluoroscopic image, forexample the catheter proximal marker 224 b may be a single band and themarker 411 on the guide sheath 400 may be a double band and any markerson a working device delivered through the distal access system can haveanother type of band or mark. The radiopaque markers 224 of the distalluminal portion 222, particularly those near the distal tip regionnavigating extremely tortuous anatomy, can be relatively flexible suchthat they do not affect the overall flexibility of the distal luminalportion 222 near the distal tip region. The radiopaque markers 224 canbe tungsten-loaded or platinum-loaded markers that are relativelyflexible compared to other types of radiopaque markers used in deviceswhere flexibility is not paramount.

As mentioned previously, the control element 230 is configured to allowdistal advancement and proximal retraction of the catheter 200 throughthe working lumen 410 of the guide sheath 400 including passage out thedistal lumen 408. In an implementation, the length of the proximalcontrol element 230 is longer than the entire length of the guide sheath400 (from distal tip to proximal valve), such as by about 5 cm to 15 cm.The length of the body 402 can be in the range of 80 to 90 cm or up toabout 100 cm or up to about 105 cm and the length of the proximalcontrol element 230 can be between 90-100 cm.

Again with respect to FIG. 3, the proximal control element 230 caninclude one or more markers 232 to indicate the overlap between thedistal luminal portion 222 of the catheter 200 and the sheath body 402as well as the overlap between the distal luminal portion 222 of thecatheter 200 and other interventional devices that may extend throughthe distal luminal portion 222. At least a first mark 232 can be an RHVproximity marker positioned so that when the mark 232 is aligned withthe sheath proximal hemostasis valve 434 during insertion of thecatheter 200 through the guide sheath 400, the catheter 200 ispositioned at the distal-most position with the minimal overlap lengthneeded to create the seal between the catheter 200 and the working lumen410. At least a second mark 232 can be a Fluoro-saver marker that can bepositioned on the control element 230 and located a distance away fromthe distal tip of the distal luminal portion 222. In someimplementations, a mark 232 can be positioned about 100 cm away from thedistal tip of the distal luminal portion 222.

The proximal control element 230 can include a gripping feature such asa tab 234 on the proximal end to make the proximal control element 230easy to grasp and advance or retract. The tab 234 can couple with one ormore other components of the system as will be described in more detailbelow. The proximal tab 234 can be designed to be easily identifiableamongst any other devices that may be inserted in the sheath proximalvalve 434, such as guidewires or retrievable stent device wires. Aportion of the proximal control element 230 and/or tab 234 can becolored a bright color, or marked with a bright color, to make it easilydistinguishable from guidewire, retrievable stent tethers, or the like.Where multiple catheters 200 are used together in a nesting fashion toreach more distal locations within the brain, each proximal controlelement 230 and/or tab 234 can be color-coded or otherwise labeled toclearly show to an operator which proximal control element 230 of whichcatheter 200 it is coupled to.

The tab 234 can be integrated with or in addition to a proximal hubcoupled to a proximal end of the control element 230. For example, aswill be described in more detail below, the proximal control element 230can be a hypotube having a lumen. The lumen of the hypotube can be influid communication with the proximal hub at a proximal end of thecontrol element 230 such that aspiration forces and/or fluids can bedelivered through the hypotube via the proximal hub.

The proximal control element 230 can be configured with sufficientstiffness to allow advancement and retraction of the distal luminalportion 222 of the catheter 200, yet also be flexible enough to navigatethrough the cerebral anatomy as needed without kinking. Theconfiguration of the proximal control element 230 can vary. In someimplementations, the proximal control element 230 can be a tubularelement having an outer diameter that is substantially identical to theouter diameter of the distal luminal portion 222 similar to a typicalcatheter device. In other implementations, the outer diameter of theproximal control element 230 is sized to avoid taking up too muchluminal area in the lumen 410 of the guide sheath 400 as describedabove.

The proximal control element 230 can be a solid metal wire that is roundor oval cross-sectional shape. The proximal control element 230 can be aflattened ribbon of wire having a rectangular cross-sectional shape asshown in FIG. 4A. The flattened ribbon of wire can also have square,rectangular, or other cross-sectional shape. The ribbon of wire can becurved into a circular, oval, c-shape, or quarter circle or othercross-sectional area along an arc. The proximal control element 230 canbe a hollow wire having a lumen 235 extending through it, such as ahypotube as shown in FIG. 4B. The hypotube can have an oval or circularshape. In an implementation, the proximal control element 230 is aribbon of stainless steel having dimensions of about 0.012″×0.020″. Inan implementation, the proximal control element 230 is a round wire,with dimensions from 0.014″ to 0.018″. In another implementation, theproximal control element 230 is a ribbon with dimensions ranging from0.010″ to 0.015″ thick, and 0.015″ thick to 0.025″ thick. In animplementation, the proximal control element 230 is a hypotube formedfrom a flattened ribbon of stiff material rolled into a tubular shape tohave a lumen 235. In some implementations, the proximal control element230 can be formed of a flattened ribbon of stainless steel and rolledinto a hypotube such that the proximal control element 230 has a wallthickness of about 0.007″, an inner diameter of about 0.004″ and anouter diameter of about 0.018″ before the hypotube is modified into anoval cross-sectional shape. The ovalized hypotube can maintain an innerdiameter that is at least 0.001″ along at least a first dimension and anouter diameter that is at least 0.015″ along at least a first dimension.In an implementation, the proximal control element 230 material is ametal such as a stainless steel or nitinol as well as a plastic such asany of a variety of polymers.

In an implementation, the proximal control element 230 is a stainlesssteel hypotube having an oval cross-sectional shape (see FIG. 4B). Theoval tubular shape can increase the column strength, pushability andkink resistance of the proximal control element 230 for improvedadvancement through tortuous anatomy. The cross-sectional area of anoval hypotube minimizes the impact of the catheter 200 on movement ofother tools through the working lumen 410 of the sheath 400. FIG. 4Cillustrates a cross-sectional view of the working lumen 410 of thesheath 400 having a proximal portion 230 extending therethrough. Theproximal portion 230 has a rectangular cross-sectional shape. FIG. 4Dillustrates a cross-sectional view of the working lumen 410 having anovalized hypotube proximal portion 230 and a catheter advancementelement 300 extending therethrough. FIG. 4E illustrates the comparisonof surface area between the rectangular-shaped ribbon and the ovalhypotube. The oval hypotube has less surface area compared to therectangular-shaped ribbon allowing for a greater flow rate through theworking lumen 410, for example, during application of aspirating forces.

Now with respect to FIGS. 5A-5F, the junction between the distal luminalportion 222 of the catheter 200 and the proximal control element 230 canbe configured to allow a smooth transition of flexibility between thetwo portions so as not to create a kink or weak point. The smoothtransition at the joint between the distal luminal portion 222 and theproximal control element 230 also allows for smooth passage of devicesthrough the contiguous inner lumen created by the working lumen 410 ofthe guide sheath 400 and the lumen 223 of the luminal portion 222 of thecatheter 200. In an implementation, the distal luminal portion 222 has atransition section 226 near where the luminal portion 222 couples to theproximal control element 230 (see FIG. 5A). The transition section 226can have an angled cut such that there is no abrupt step transition fromthe working lumen 410 of the guide sheath 400 to the inner lumen 223 ofthe catheter 200. The angled cut can be generally planer. In analternate implementation, the angled cut is curved or stepped to providea more gradual transition zone. It should be appreciated that theproximal end region of the distal luminal portion 222 can be angled inan oblique manner relative to a longitudinal axis of the catheter 200such that the proximal end and proximal opening into the lumen are at anangle other than 90° to the longitudinal axis of the catheter 200, forexample between approximately 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°,or 45° up to less than 90°. The proximal end region of the distalluminal portion 222 can also be aligned substantially perpendicular tothe longitudinal axis of the catheter 200 such that the proximal end andproximal opening into the lumen are substantially 90° to thelongitudinal axis of the catheter 200. Similarly, the distal end regionof the distal luminal portion 222 can be angled in an oblique mannerrelative to a longitudinal axis of the catheter 200 such that the distalend and distal opening from the lumen 223 are at an angle other than 90°to the longitudinal axis of the catheter 200, for example betweenapproximately 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, or 45° up toless than 90°. The distal end region of the distal luminal portion 222can also be aligned substantially perpendicular to the longitudinal axisof the catheter 200 such that the distal end and distal opening into thelumen are substantially 90° to the longitudinal axis of the catheter200.

The proximal control element 230 can be coupled to a proximal end regionof the catheter 200 and/or may extend along at least a portion of thedistal luminal portion 222 such that the proximal control element 230couples to the distal luminal portion 222 a distance away from theproximal end. The proximal control element 230 can be coupled to thedistal luminal portion 222 by a variety of mechanisms including bonding,welding, gluing, sandwiching, stringing, tethering, or tying one or morecomponents making up the proximal control element 230 and/or portion222. The distal luminal portion 222 and the proximal control element 230may be joined by a weld bond, a mechanical bond, an adhesive bond, orsome combination thereof. In some implementations, the proximal controlelement 230 and luminal portion 222 are coupled together by sandwichingthe proximal control element 230 between layers of the distal luminalportion 222. For example, the proximal control element 230 can be ahypotube or rod having a distal end that is skived, ground or cut suchthat the distal end can be laminated or otherwise attached to the layersof the catheter portion 222 near a proximal end region. The region ofoverlap between the distal end of the proximal control element 230 andthe portion 222 can be at least about 1 cm. This type of coupling allowsfor a smooth and even transition from the proximal control element 230to the luminal portion 222.

Still with respect to FIGS. 5A-5F, the transition section 226 of thedistal luminal portion 222 can open up into a trough 238 extending alength proximal to the transition section 226. In some implementations,the trough 238 has a cross-sectional geometry that is substantiallycurved. For example, the trough 238 can extend along an arc of thelongitudinal axis of the catheter 200 between about 20 to about 90degrees. In other implementations, the edges of the trough 238 curvesuch that the trough 238 is not substantially flat. In otherimplementations, the trough 238 is substantially flat. The trough 238can provide a smooth transition between distal luminal portion 222 andproximal control element 230 when the device is forced to bend. This canreduce the likelihood of kinking and facilitate pushing againstresistance.

The distal end of the proximal control element 230 and/or the distalluminal portion 222 may have features that facilitate a mechanical jointduring a weld, such as a textured surface, protruding features, orcut-out features. During a heat weld process, the features wouldfacilitate a mechanical bond between the polymer distal luminal portion222 and the proximal control element 230. For example, as shown in FIGS.6A-6F the proximal end of the distal luminal portion 222 can include ashort mating sleeve 240 coupled to a proximal edge 221 of the distalluminal portion 222. The sleeve 240 can include an inner lumen extendingbetween a proximal opening 242 and a distal opening 241. The distal endof the proximal control element 230 can insert through the proximalopening 242 and within the inner lumen of the sleeve 240 to couple theproximal control element 230 to the distal luminal portion 222. In someimplementations, the proximal control element 230 can couple with thedistal luminal portion 222 such that a distal opening 231 of thehypotube forming the proximal control element 230 can communicate withthe lumen 223 of the distal luminal portion 222, for example, throughthe distal opening 241 of the sleeve 240. The sleeve 240 can alsoprovide transition between distal luminal portion 222 and proximalcontrol element 230 similar to the trough 238. The distal luminalportion 222 need not include a mating sleeve 240 to couple with theproximal control element 230. For example, the distal end of theproximal control element 230 can insert through a wall of the trough 238at the proximal end of the distal luminal portion 222 (see FIG. 5A,5E-5F). The distal end of the proximal control element 230 can extendalong the length of the trough 238 and along at least a length of thewall of the distal luminal portion 222.

As mentioned above, the luminal portion 222 of the catheter 200 can havea uniform diameter from a proximal end to a distal end or the luminalportion 222 can have different outer diameters along its length. Forexample, the distal-most end of the distal luminal portion 222 can havea smaller outer diameter compared to a more proximal region of thedistal luminal portion 222. FIGS. 5A-5B, 5E-5F as well as FIGS. 6A-6B,6E-6F show a distal luminal portion 222 having a distal tubular regionor distal tube 245 having a smaller outer diameter and a proximaltubular region or proximal tube 246 have a larger outer diameter. Thedistal tube 245 transitions via a step-up 247 to the proximal tube 246.As best shown in FIGS. 5A and 6A, the inner diameters of distal tube 245and the proximal tube 246 are substantially the same providing a smoothinner wall surface for the lumen 223. The outer diameter of the distaltube 245 is smaller than the outer diameter of the proximal tube 246.The step-up 247 is formed by a transition in wall thickness between thedistal tube 246 and the proximal tube 247. In some implementations, theouter diameter of the distal tube 246 can be about 0.080″ to about0.084″ and the outer diameter of the proximal tube 247 can be about0.087″ to about 0.088″.

At least a portion of the wall of the larger outer diameter proximaltube 246 can be discontinuous such that it include a slit 236 (see FIGS.5A-5C, 5E-5F, 6A-6C, and 6E-6F). The slit 236 can extend a distancealong the length of the proximal tube 246. The slit 236 can extend froman edge 221 of the proximal tube 246 at least about 2 cm of a length ofthe proximal tube 247. The slit 236 can, but need not, extend along theentire length of the proximal tube 247 to the location of the step-up247. Additionally, the proximal tube 247 can include more than one slit236. The slit 236 can be positioned in the larger diameter proximal tube246 at a location opposite from where the distal end of the proximalcontrol element 230 couples with the wall of the distal luminal portion222. As such that distal end of the proximal control element 230embedded within the wall of the proximal tube 246 lies opposite the slit236 (see FIGS. 5C and 6C). It should be appreciated that the slit 236can be positioned around the proximal tube 246 at another location.

The slit 236 can allow for the proximal tube 246 to expand slightly suchthat the ends of the wall forming the slit 236 separate forming a gaptherebetween. For example, upon insertion of the catheter 200 throughthe working lumen 410 of the sheath 400, the outer diameter can bereceived in a sliding fit such that at least an overlap region 348remains. Upon application of an aspirational force through the workinglumen 410, for example, by applying suction from an aspiration sourcecoupled to the proximal end 403 of the guide sheath 400, the sealingprovided at the overlap region 348 can be enhanced by a slight wideningof the gap formed by the slit 236. This slight expansion provides forbetter sealing between the outer diameter of the proximal tube 246 andthe inner diameter of the working lumen 410 of the sheath 400 becausethe outer surface of the walls of the catheter 200 can press against theinner surface of the working lumen 410 creating a tight fit between thecatheter 200 and the sheath 400. This improved sealing between the outersurface of the catheter 200 and the inner surface of the working lumen410 minimizes the seepage of blood from the vessel into the workinglumen 410 directly through the distal opening 408. Thus, the largerouter diameter of the proximal tube 246 in combination with the slit 236can enhance sealing between the catheter 200 and the sheath 400 byaccommodating for variations of sheath inner diameters. The slit 236 caneffectively increase the outer diameter of the proximal tube 246depending on whether the walls forming the slit 236 are separated adistance. The walls forming the slit 236 can separate away from oneanother and increase a width of slit. The outer diameter of the proximaltube 246 including the increased width upon separation of the wallsforming the slit 236 can be the same size or larger than the innerdiameter of the sheath through which the proximal tube 246 is inserted.This allows for a single catheter to be compatible with a larger rangeof inner diameters. In some implementations, the outer diameter of theproximal tube 246 can be 0.081″ when the walls forming the slit 236 abutone another and no gap is present. The outer diameter of the proximaltube 246 can increase up to about 0.087″ when the walls forming the slit236 are separated a maximum distance away from one another.Additionally, the increased wall thickness of the proximal tube 246allows for creating a more robust joint between the distal luminalportion 222 and the proximal control element 230 of the catheter.

Catheter Advancement Element

As mentioned above the distal access system 100 can, but need not,include a catheter advancement element 300 for delivery of the catheter200 to the distal anatomy. It should be appreciated that where thecatheter 200 is described herein as being used together or advanced withthe catheter advancement element 300 that the catheter advancementelement 200 need not be used to deliver the catheter 200 to a targetlocation. For example, other advancement tools are to be consideredherein, such as a microcatheter and/or guidewire as is known in the art.Similarly, the catheter advancement element 300 can be used together toadvance other catheters besides the catheter 200 described herein. Forexample, the catheter advancement element 300 can be used to deliver a5MAX Reperfusion Catheter (Penumbra, Inc. Alameda, Calif.) for clotremoval in patients with acute ischemic stroke or other reperfusioncatheters known in the art. Although the catheter advancement element300 is described herein in reference to catheter 200 it should beappreciated that it can be used to advance other catheters and it is notintended to be limiting to its use.

As described above, the distal access system 100 is capable of providingquick and simple access to distal target anatomy, particularly thetortuous anatomy of the cerebral vasculature. The flexibility anddeliverability of the distal access catheter 200 allow the catheter 200to take the shape of the tortuous anatomy and avoids exertingstraightening forces creating new anatomy. The distal access catheter200 is capable of this even in the presence of the catheter advancementelement 300 extending through its lumen. Thus, the flexibility anddeliverability of the catheter advancement element 300 is on par orbetter than the flexibility and deliverability of the distal luminalportion 222 of the distal access catheter 200 in that both areconfigured to reach the middle cerebral artery (MCA) circulation withoutstraightening out the curves of the anatomy along the way.

The catheter advancement element 300 can include a non-expandable,flexible elongate body 360 coupled to a proximal portion 366. Theelongate body 360 can be received within and extended through theinternal lumen 223 of the distal luminal portion 222 of the catheter 200(see FIG. 2B). A distal tip 346 of the catheter advancement element 300can be extended beyond the distal end of the catheter 200 as shown inFIG. 2B. The proximal portion 366 of the catheter advancement element300 is coupled to a proximal end region of the elongate body 360 andextends proximally therefrom. The proximal portion 366 can be lessflexible than the elongate body 360 and configured for bi-directionalmovement of the elongate body 360 of the catheter advancement element300 within the luminal portion 222 of the catheter 200, as well as formovement of the catheter system 100 as a whole. The elongate body 360can be inserted in a coaxial fashion through the internal lumen 223 ofthe luminal portion 222. The outer diameter of at least a region of theelongate body 360 can be sized to substantially fill the internal lumen223 of the luminal portion 222.

The overall length of the catheter advancement element 300 (e.g. betweenthe proximal end through to the distal-most tip) can vary, but generallyis long enough to extend through the support catheter 200 plus at leasta distance beyond the distal end of the support catheter 200 while atleast a length of the proximal portion 366 remains outside the proximalend of the guide sheath 400. In some implementations, the overall lengthof the catheter advancement element 300 is about 149 cm and a workinglength of 143 cm from a proximal tab or hub to the distal-most tip. Theelongate body 360 can have a length that is at least as long as theluminal portion 222 of the catheter 200 although it should beappreciated the elongate body 360 can be shorter than the luminalportion 222 so long as at least a length remains inside the luminalportion 222 when a distal portion of the elongate body 360 is extendeddistal to the distal end of the luminal portion 222. In someimplementations, the shaft length of the distal luminal portion 222 canbe about 39 cm and the insert length of the elongate body 360 can be atleast about 48.5 cm, 49 cm, or about 49.5 cm. The proximal portion 366can have a length that varies as well. In some implementations, theproximal portion 366 is about 94 cm. The distal portion extending distalto the distal end of the luminal portion 222 can include distal tip 346that protrudes a length beyond the distal end of the luminal portion 222during use of the catheter advancement element 300. The distal tip 346of the elongate body 360 that is configured to protrude distally fromthe distal end of the luminal portion 222 aids in the navigation of thecatheter system through the tortuous anatomy of the cerebral vessels, aswill be described in more detail below. The proximal portion 366 coupledto and extending proximally from the elongate body 360 can aligngenerally side-by-side with the proximal control element 230 of thecatheter 200. The arrangement between the elongate body 360 and theluminal portion 222 can be maintained during advancement of the catheter200 through the tortuous anatomy to reach the target location fortreatment in the distal vessels and aids in preventing the distal end ofthe catheter 200 from catching on tortuous branching vessels, as will bedescribed in more detail below.

In some implementations, the elongate body 360 can have a region ofrelatively uniform outer diameter extending along at least a portion ofits length and the distal tip 346 tapers down from the uniform outerdiameter. When the catheter advancement element 300 is inserted throughthe catheter 200, this tapered distal tip 346 is configured to extendbeyond and protrude out through the distal end of the luminal portion222 whereas the more proximal region of the body 360 having a uniformdiameter remains within the luminal portion 222. As mentioned, thedistal end of the luminal portion 222 can be blunt and have no change inthe dimension of the outer diameter whereas the distal tip 346 can betapered providing an overall elongated tapered geometry of the cathetersystem. The outer diameter of the elongate body 360 also approaches theinner diameter of the luminal portion 222 such that the step-up from theelongate body 360 to the outer diameter of the luminal portion 222 isminimized. Minimizing this step-up prevents issues with the lip formedby the distal end of the luminal portion 222 catching on the tortuousneurovasculature, such as around the carotid siphon near the ophthalmicartery branch, when the distal tip 346 bends and curves along within thevascular anatomy. In some implementations, the inner diameter of theluminal portion 222 can be 0.072″ and the outer diameter of the elongatebody 360 is 0.070″ such that the difference between them is only 2thousandths of an inch. In other implementations, the outer diameter ofthe elongate body 360 is 0.062″. Despite this, the luminal portion 222and the elongate body 360 extending through it in co-axial fashion areflexible enough to navigate the tortuous anatomy leading to the level ofM1 or M2 arteries without kinking and without damaging the vessel.

The length of the distal tip 346 can vary. In some implementations, thelength of the distal tip 346 can be in a range of between about 0.50 cmto about 3.0 cm from the distal-most terminus of the elongate body 360.In other implementations, the length of the distal tip 346 is between2.0 cm to about 2.5 cm. In some implementations, the length of thedistal tip 236 varies depending on the inner diameter of the elongatebody 360. For example, the length of the distal tip 236 can be as shortas 0.5 cm and the inner diameter can be 0.054″. The distal tip 346 canbe a constant taper from the outer diameter of the elongate body 360down to a second smaller outer diameter at the distal-most tip. Theconstant taper of the distal tip 346 can be from 0.062″ outer diameterto about 0.031″ outer diameter. The length of the constant taper of thedistal tip 346 can vary, for example, between 1 cm and 3 cm, or between2.0 cm and 2.5 cm.

It should be appreciated that the distal tip 346 need not taper and canachieve its soft, atraumatic and flexible characteristic due to amaterial property other than due to a change in outer dimension tofacilitate endovascular navigation to an embolus in tortuous anatomy.Additionally or alternatively, the distal tip 346 of the elongate body360 can have a transition in flexibility along its length. The mostflexible region of the distal tip 346 can be its distal terminus. Movingalong the length of the distal tip 346 from the distal terminus towardsa region proximal to the distal terminus, the flexibility can graduallyapproach the flexibility of the distal end of the luminal portion 222.For example, the distal tip 346 can be formed of a material having ahardness of 35D and transitions proximally towards increasingly hardermaterials having a hardness of 55D and 72D up to the proximal portion366, which can be a stainless steel hypotube, or a combination of amaterial property and tapered shape. The materials used to form theregions of the elongate body 360 can include Pebax (such as Pebax 25D,35D, 55D, 72D) with a lubricious additive compound. Incorporation of alubricious additive directly into the polymer elongate body meansincorporation of a separate lubricious liner, such as a Teflon liner, isunnecessary. This allows for a more flexible element that can navigatethe distal cerebral anatomy and is less likely to kink. Similarmaterials can be used for forming the distal luminal portion 222 of thecatheter 200 providing similar advantages. It should also be appreciatedthat the flexibility of the distal tip 346 can be achieved by acombination of flexible lubricious materials and tapered shapes. Forexample, the length of the tip 346 can be kept shorter than 2 cm-3 cm,but maintain optimum deliverability due to a change in flexible materialfrom distal-most tip towards a more proximal region a distance away fromthe distal-most tip. In an implementation, the elongate body 360 isformed of PEBAX (polyether block amide) embedded silicone designed tomaintain the highest degree of flexibility. It should be appreciatedthat the wall thickness of the distal end of the luminal portion 222 canalso be made thin enough such that the lip formed by the distal end ofthe luminal portion 222 relative to the elongate body 360 is minimized.

As mentioned above, the elongate body 360 can be constructed to havevariable stiffness between the distal and proximal ends of the elongatebody 360. The flexibility of the elongate body 360 is highest at thedistal-most terminus of the distal tip 346 and can gradually transitionin flexibility to approach the flexibility of the distal end of theluminal portion 222, which is typically less flexible than thedistal-most terminus of the distal tip 346. Upon inserting the catheteradvancement element 300 through the catheter 200, the region of theelongate body 360 extending beyond the distal end of the luminal portion222 can be the most flexible and the region of the elongate body 360configured to be aligned with the distal end of the luminal portion 222during advancement in the vessel can have a substantially identicalflexibility as the distal end of the luminal portion 222 itself. Assuch, the flexibility of the distal end of the luminal portion 222 andthe flexibility of the body 360 just proximal to the extended portion(whether tapered or having no taper) can be substantially the same. Thisprovides a smooth transition in material properties to improve trackingof the catheter system through tortuous anatomy. Further, the moreproximal sections of the elongate body 360 can be even less flexible andincreasingly stiffer. It should be appreciated that the change inflexibility of the elongate body 360 can be a function of a materialdifference, a dimensional change such as through tapering, or acombination of the two. The elongate body 360 has a benefit over amicrocatheter in that it can have a relatively large outer diameter thatis just 0.003″-0.010″ smaller than the inner diameter of the catheter200 and still maintain a high degree of flexibility for navigatingtortuous anatomy.

The elongate body 360 can be formed of various materials that provide asuitable flexibility and lubricity. Example materials include highdensity polyethylene, 72D PEBAX, 90D PEBAX, or equivalent stiffness andlubricity material. The flexibility of the elongate body 360 canincrease towards the distal tip such that the distal region of theelongate body 360 is softer, more flexible, and articulates and bendsmore easily than a more proximal region. For example, a more proximalregion of the elongate body can have a bending stiffness that isflexible enough to navigate tortuous anatomy such as the carotid siphonwithout kinking.

In some implementations, the elongate body 360 can be generally tubularalong at least a portion of its length such that it has a lumen 368extending parallel to a longitudinal axis of the catheter advancementelement 300 (see FIG. 7A-7C). In an implementation, the lumen 368 of theelongate body 360 is sized to accommodate a guidewire, however it shouldbe appreciated that use of the catheter advancement element 300generally eliminates the need for a guidewire lead. The guidewire canextend through the lumen 368 from a proximal opening to a distal openingthrough which the guidewire can extend. In some implementations, theproximal opening is at the proximal end of the catheter advancementelement 300 such that the catheter advancement element 300 is configuredfor over-the-wire (OTW) methodologies. In other implementations, theproximal opening is a rapid exchange opening 362 such that the catheteradvancement element 300 is configured for rapid exchange rather than orin addition to OTW. In this implementation, the proximal opening 362 islocated a distance away from a proximal tab 364 and distal to theproximal portion 366 (see FIGS. 7A-7B and 7D). The lumen 368 of theelongate body 360 can be configured to receive a guidewire in the rangeof 0.014″ and 0.018″ diameter, or in the range of between 0.014″ and0.022″. In this implementation, the inner luminal diameter of theelongate body 360 can be between 0.020″ and 0.024″. The guidewire, thecatheter advancement element 300, and the catheter 200 can all beassembled co-axially for insertion through the working lumen 410 of theguide sheath 400. The inner diameter of the lumen 368 of the elongatebody 360 can be 0.019″ to about 0.021″.

FIG. 7D shows another implementation of the catheter advancement element300 configured for rapid exchange. Rapid exchange configurations candramatically shorten device length, decreases staffing requirements, andreduces fluoroscopy. As with other implementations described herein, thecatheter advancement element 300 can include a non-expandable, flexibleelongate body 360 coupled to a proximal portion 366 coupled to aproximal tab 364 or hub 375. As described elsewhere herein, the regionnear the distal tip 346 can be tapered such that the outer diametertapers over a length of between 1 cm to about 3 cm. In someimplementations, the distal taper length is 2.5 cm. In someimplementations, the distal tip 346 tapers from about 0.080″ to about0.031″. Also as described elsewhere herein, the distal tip 346 can beformed of a material having a hardness of 35D and transitions proximallytowards increasingly harder materials having a hardness of 55D and 72Dup to the proximal portion 366. For example, FIG. 7D illustrates segment371 of the elongate body 360 including the distal tip 346 can have ahardness of 35D and a length of about 10 cm. Segment 372 of the elongatebody 360 can have a hardness of 55D and have a length of about 8 cm.Segment 373 of the elongate body 360 can have a hardness of 72D can beabout 31 cm in length. The three segments 371, 372, 373 combined canform an insert length of the elongate body 360 from where the proximalportion 366 couples to the elongate body 360 to the terminus of thedistal tip 346 that can be about 49 cm in length.

Still with respect to FIG. 7D, an entry port 362 for a proceduralguidewire 805 can be positioned a distance away from the distal-most endof the elongate body 360. In some implementations, the entry/exit port362 can be about 18 cm from the distal-most end creating a rapidexchange wire entry/exit segment 370. The outer diameter of the elongatebody 360 within segment 370 (segments 371 and 372) can be about0.080″-0.082″ whereas segment 373 proximal to this rapid exchange wireentry/exit segment 370 can have a step-down in outer diameter such asabout 0.062″-0.064″.

In other implementations, the entire catheter advancement element 300can be a tubular element configured to receive a guidewire through boththe proximal portion 366 as well as the elongate body 360. For example,the proximal portion 366 can be a hypotube or tubular element having alumen that communicates with the lumen 368 extending through theelongate body 360 (shown in FIG. 3). In some implementations, theproximal portion 366 can be a skived hypotube of stainless steel coatedwith PTFE having an outer diameter of 0.026″. In other implementations,the outer diameter can be between 0.024″ and 0.030″. In someimplementations, such as an over-the-wire version, the proximal portion366 can be a skived hypotube coupled to a proximal hub 375. The proximalportion 366 can extend eccentric or concentric to the distal luminalportion 222. As best shown in FIG. 7E, the proximal portion 366 can be astainless steel hypotube as described elsewhere herein. The hypotube canhave a lubricious coating such as PTFE. The hypotube can have an innerdiameter of about 0.021″, an outer diameter of about 0.0275″, and anoverall length of about 94 cm providing a working length for thecatheter advancement element 300 that is about 143 cm. Including theproximal hub 375, the catheter advancement element 300 can have anoverall length of about 149 cm. In some implementations, the hypotubecan be a tapered part with a length of about 100 mm, starting proximalwith a thickness of 0.3 mm and ending with a thickness of 0.10 mm to0.15 mm. In still further implementations, the elongate body 360 can bea solid element coupled to the proximal portion 366 having no guidewirelumen.

As best shown in FIGS. 7F-7J, the proximal end of the hypotube can becoupled to a proximal hub 375. The proximal hub 375 can be anover-molded component having a luer thread 377 and a luer taper 378formed on an inside of the proximal hub 375. The proximal hub 375 canincorporate a tab 364 providing for easier gripping by a user. Theproximal hub 375 prevents advancement of the catheter advancementelement 300 and the catheter 200 beyond the distal tip of the basesheath 400 or guide catheter by limiting insertion into the proximal RHV434 providing critical functional and safety features for properoperation of the system 10.

At least a portion of the solid elongate body 360, such as the elongatedistal tip 346, can be formed of or embedded with or attached to amalleable material that skives down to a smaller dimension at a distalend. The distal tip 346 can be shaped to a desired angle or shapesimilar to how a guidewire may be used. The malleable length of theelongate body 360 can be at least about 1 cm, 3 cm, 5 cm, and up toabout 10 cm, 15 cm, or longer. In some implementations, the malleablelength can be about 1%, 2%, 5%, 10%, 20%, 25%, 50% or more of the totallength of the elongate body 360. In some implementations, the catheteradvancement element 300 can have a working length of about 140 cm toabout 143 cm and the elongate body 360 can have an insert length ofabout 49 cm. The insert length can be the PEBAX portion of the elongatebody 360 that is about 49.5 cm. As such that malleable length of theelongate body 360 can be between about 0.5 cm to about 25 cm or more.The shape change can be a function of a user manually shaping themalleable length prior to insertion. Alternatively, the shape change canbe a reversible and actuatable shape change such that the tip forms theshape upon activation by a user such that the tip can be used in astraight format until a shape change is desired by the user.

It should be appreciated that the elongate body 360 can extend along theentire length of the catheter 200, including the distal luminal portion222 and the proximal control element 230 or the elongate body 360 canincorporate the proximal portion 366 that aligns generally side-by-sidewith the proximal control element 230 of the catheter 200, as describedabove. The proximal portion 366 of the elongate body 360 can bepositioned co-axial with or eccentric to the elongate body 360. Theproximal portion 366 of the elongate body 360 can have a lumen extendingthrough it. Alternatively, the portion 366 can be a solid rod or ribbonhaving no lumen.

Again with respect to FIGS. 7a -7D, like the distal luminal portion 222of the catheter 200, the elongate body 360 can have one or moreradiopaque markers 344 along its length. The one or more markers 344 canvary in size, shape, and location. One or more markers 344 can beincorporated along one or more parts of the catheter advancement element300, such as a tip-to-tip marker, a tip-to-taper marker, an RHVproximity marker, a Fluoro-saver marker, or other markers providingvarious information regarding the relative position of the catheteradvancement element 300 and its components. In some implementations andas best shown in FIG. 7C, a distal end region can have a firstradiopaque marker 344 a and a second radiopaque marker 344 b can belocated to indicate the border between the tapering of the distal tip346 and the more proximal region of the elongate body 360 having auniform or maximum outer diameter. This provides a user with informationregarding an optimal extension of the distal tip 346 relative to thedistal end of the luminal portion 222 to minimize the lip at this distalend of the luminal portion 222 for advancement through tortuous anatomy.In other implementations, for example where the distal tip 346 is notnecessarily tapered, but instead has a change in overall flexibilityalong its length, the second radiopaque marker 344 b can be located toindicate the region where the relative flexibilities of the elongatebody 360 (or the distal tip 346 of the elongate body 360) and the distalend of the luminal portion 222 are substantially the same. The markermaterial may be a platinum/iridium band, a tungsten, platinum, ortantalum-impregnated polymer, or other radiopaque marker that does notimpact the flexibility of the distal tip 346 and elongate body 360. Insome implementations, the radiopaque markers are extruded Pebax loadedwith tungsten for radiopacity. In some implementations, the proximalmarker band can be about 2.0 mm wide and the distal marker band can beabout 2.5 mm wide to provide discernable information about the distaltip 346.

As mentioned above, the proximal control element 230 of the catheter 200can include a proximal tab 234 on the proximal end of the proximalcontrol element 230. Similarly, the proximal portion 366 coupled to theelongate body 360 can include a tab 364. The tabs 234, 364 can beconfigured to removably and adjustable connect to one another and/orconnect to their corresponding proximal portions. The coupling allowsthe catheter advancement element 300 to reversibly couple with thecatheter 200 to lock (and unlock) the relative extension of the distalluminal portion 222 and the elongate body 360. This allows the catheter200 and the catheter advancement element 300 to be advanced as a singleunit. In the locked configuration, the tab 364 or proximal portion 366can be engaged with the catheter tab 234. In the unlocked configuration,the tab 364 may be disengaged from the catheter tab 234. The tab 364 orproximal portion 366 may attach, e.g., click or lock into, the cathetertab 234 in a fashion as to maintain the relationships of correspondingsection of the elongate body 360 and the catheter 200 in the lockedconfiguration. It should be appreciated that the tab 364 can be afeature on the proximal hub 375 such as the hub 375 shown in FIGS.7F-7J.

Such locking may be achieved by, e.g., using a detent on the tab 364that snaps into place within a recess formed in the catheter tab 234, orvice versa. For example, the tab 234 of the catheter 200 can form a ringhaving a central opening extending therethrough. The tab 364 of the body360 can have an annular detent with a central post sized to insertthrough the central opening of the tab 234 such that such that the ringof the tab 234 is received within the annular detent of tab 364 forminga singular grasping element for a user to advance and/or withdraw thecatheter system through the access sheath. The tabs 234, 364 may beaffixed or may be slideable to accommodate different relative positionsbetween the elongate body 360 and the luminal portion 222 of thecatheter 200. In some implementations, a proximal end of the proximalcontrol element 230 of the catheter 200 can include a coupling feature334, such as clip, clamp, c-shaped element or other connector configuredto receive the proximal portion 366 of the catheter advancement element300 (see FIG. 2A). The coupling feature 334 can be configured to snaptogether with the proximal portion 366 through an interference fit suchthat a first level of force is needed in order to insert the proximalportion 366 into the clip of the tab 234 and a second, greater level offorce is needed to remove the proximal portion 366 from the clip of thetab 234. However, upon inserting the proximal portion 366 into thecoupling feature 334 the catheter advancement element 300 and thecatheter 200 can still be slideably adjusted relative to one anotheralong a longitudinal axis of the system. The amount of force needed toslideably adjust the relative position of the two components can be suchthat inadvertent adjustment is avoided and the relative position can bemaintained during use, but can be adjusted upon conscious modification.It should be appreciated that the configuration of the coupling betweenthe proximal portion 366 of the catheter advancement element 300 and theproximal extension 360 of the catheter 200 can vary. Generally, however,the coupling is configured to be reversible and adjustable while stillproviding adequate holding power between the two elements in a mannerthat is relatively user-friendly (e.g. allows for one-handed use) andorganizes the proximal ends of the components (e.g. prevents theproximal extension 360 and proximal portion 366 from becoming twistedand entangled with one another). It should also be appreciated that thecoupling feature 334 configured to prevent entanglement and aid in theorganization of the proximal portions can be integrated with the tabs orcan be a separate feature located along their proximal end region.

The catheter advancement element 300 can be placed in a lockedconfiguration with the catheter 200 configured for improved trackingthrough a tortuous and often diseased vasculature in acute ischemicstroke. Other configurations are considered herein. For example, theelongate body 360 can include one or more detents on an outer surface.The detents can be located near a proximal end region and/or a distalend region of the elongate body 360. The detents are configured to lockwith correspondingly-shaped surface features on the inner surface of theluminal portion 222 through which the elongate body 360 extends. Thecatheter advancement element 300 and the catheter 200 can haveincorporate more than a single point of locking connection between them.For example, a coupling feature 334, such as clip, clamp, c-shapedelement or other connector configured to hold together the catheteradvancement element 300 and proximal control element 230 or tab 234 ofthe catheter 200 as described elsewhere herein.

In some implementations, the proximal control element 230 of thecatheter 200 can run alongside or within a specialized channel of theproximal portion 366. The channel can be located along a length of theproximal portion 366 and have a cross-sectional shape that matches across-sectional shape of the catheter proximal control element 230 suchthat the proximal control element 230 of the catheter 200 can bereceived within the channel and slide smoothly along the channelbi-directionally. Once the catheter 200 and elongate body 360 are fixed,the combined system, i.e., the catheter 200-catheter advancement element300 may be delivered to a target site, for example through the workinglumen 410 of the guide sheath 400 described elsewhere herein.

Intracranial Delivery System

Described herein are intracranial delivery systems that allow for thedelivery of stent retriever, intracranial stent, flow diverter or othermicrocatheter-delivered device through a conduit created by the supportcatheter 200 extending distally from the guide sheath 400. In someimplementations, the intracranial delivery system (IDS) is a rapidexchange system that allows for a single operator to perform all stepsin the distal access and device delivery. As will be described in moredetail below, the intracranial delivery system allows for “pushing” ofthe interventional device through only a short length (e.g. 10-20 cm) ofthe microcatheter lumen as opposed to up an entire microcatheter lumen.

FIGS. 8A-8C illustrate various systems 10 including a single operatorintracranial working device delivery system 700 configured to bedelivered through a support catheter 200 of a distal access system 100for accessing and removing a cerebral occlusion to treat acute ischemicstroke. The intracranial delivery system 700 can include a workingdevice 500 for treatment of the cerebral occlusion and configured to behoused within a microcatheter 600. The intracranial delivery system 700can optionally include a procedural guidewire 805 for delivery of thesupport catheter 200 extending through the guide sheath 400 of thedistal access system 100 as well as for delivery of the microcatheter600 pre-loaded with a working device 500.

The working device 500 can be a stent retriever (e.g. Solitaire byMedtronic or Trevo by Stryker), stent (e.g. self-expanding or balloonexpandable), flow diverter, and other devices known in the art. Theworking device 500 can include a distal, expandable payload 505 coupledto a proximal control element 510 or push wire coupled to a proximal endof the expandable payload 505. The payload 505 can be collapsed andhoused within a portion of the microcatheter 600 as will be described inmore detail below. The proximal control element 230 of the catheter 200and the proximal control element 510 of the working device 500 canextend outside the proximal end of the guide sheath 400 such that theycan be used to control the interrelationship of the microcatheter 600housing the working device 500 with the catheter 200. In someimplementations, the proximal control element 510 of the working device500 can be removable such as when the working device 500 is a stent orother type of interventional device intended to be left in place withinthe vasculature. The proximal control element 510 can be a spine, pushwire, push tube, or other element having any of a variety ofconfiguration that allows for the control element 510 to be used forbi-directional movement of the working device 500 relative to the othercomponents of the IDS 700 and/or the distal access system 100, forexample to advance and position an expandable payload 505 relative tothe lumen 605 of the microcatheter 600. The proximal control element 510can be a tubular element that is hollow or can be a solid wire, rod,ribbon or other type of structure. The working device 500 can includeone or more markers 545 along its length. In some implementations, theworking device 500 includes one or more radiopaque markers 545positioned near the payload 505, such as at the distal tip, middleregions, and/or just proximal to the expandable payload 505. The workingdevice 500 can also include one or more markers 545 on a region of theproximal control element 510 that are readily visible to an operatoroutside the RHV 434 that show the position of the payload 505 relativeto the microcatheter 600, the guidewire 805, and/or the support catheter200 without the need for fluoroscopy.

Again with respect to FIG. 8A-8C, the intracranial delivery system 700also includes a microcatheter 600. The microcatheter 600 is designedsuch that at least a portion of its length (i.e. the portion extendingbeyond the distal catheter 200) can navigate independently through theneurovasculature (e.g. the bony petrous portion of the carotid and thecarotid siphon) into the anterior circulation of the cerebral vascularanatomy. For example, by incorporating sufficient structuralreinforcement without kinking or collapsing during delivery. Themicrocatheter 600 can have a single lumen configured for rapid exchangedelivery.

In some implementations, the microcatheter 600 can have a distalmicrocatheter portion 615, a payload portion 620 located proximal to thedistal portion 615, and a proximal control element 625. As will bedescribed in more detail below, each of these portions of themicrocatheter 600 can be designed to have different flexibilitiesdepending on whether the portion will extend outside the distal accesssystem (e.g. the distal portion 615) or remain inside the conduitprovided by the distal access system (e.g. the proximal control element625).

The distal microcatheter portion 615 is designed to be very flexible anddeliverable such that it can be extended beyond the distal end of thesupport catheter 200 and be used to independently navigate the distaltortuosity. For example, the distal portion 615 can be used to navigatethe cervical loop portion such as from the petrous carotid to the Circleof Willis with minimal straightening force. The distal portion 615 isdesigned to be the only portion of the microcatheter 600 that exits thedistal access catheter 200 and interacts directly with thecerebrovascular anatomy while the stiffer portions such as the proximalcontrol element 625 of the microcatheter 600 remains within the distalaccess catheter 200.

The length of the distal portion 615 can vary, but is generally between10 cm-20 cm long. In some implementations, the distal portion 615 isbetween 12 cm up to about 15 cm. In some implementations, the distalportion 615 is between 15 cm-18 cm long. In other implementations, thedistal portion 615 is at least 18 cm long. This length allows the distalportion 615, which is the most flexible region of the microcatheter 600,to reach the M2 level when, for example, the support catheter 200 isadvanced only to the level of the petrous carotid while the remainder ofthe microcatheter 600, including the stiffer intermediate portionextending between 15 cm-30 cm proximal to the distal portion 615, isshielded by the conduit provided by the distal access system 100 (e.g.within the cervical carotid). Thus, the less deliverable part of themicrocatheter 600 remains sheathed and is prevented from causingstraightening forces to the tortuous anatomy as described elsewhereherein.

The distal, more flexible region can be about 18 cm in length whereasthe stiffer portion can be between 15-30 cm in length. The proximalcontrol element 625 can be much longer such as between 90 cm-115 cm inlength. Generally, the length of the microcatheter 600 as well as theworking device 500 are relatively short compared to conventional stentretriever systems. The length of the proximal control element 625 can bemaintained such that the proximal control element 625 combined with theintermediate stiffness portion of the microcatheter 600 are no longerthan the overall length of the spined distal catheter 200. This relativelength ensures the only portion of the microcatheter 600 that can extenddistal to the distal access system to interact with the artery is thedistal-most flexible portion 615. In some implementations, the overalllength of the delivery system 700 can be between 120 cm-150 cm.

The collapsed payload 505 of the working device 500 can be housed withinthe payload portion 620 of the microcatheter 600. The payload portion620, in comparison to the lengths provided above, can be much shorter.In some implementations, the payload portion 620 can be between 4 cm-8cm in length. The collapsed working device 500 can be advanced as a unitwithin the payload portion 620 of the microcatheter 600 to a targetlocation. This prevents the need for advancing a “bare” payload 505through the entire length of a microcatheter 600 and eliminates frictionand push-pull hassle of pushing the working device 500 such a greatdistance on its own. In some implementations, the payload portion 620can have an outer diameter that is larger or similar in size to adiameter of a conventional microcatheter, which is typically 3 F.Generally, the outer diameter of the payload portion 620 is sized to bereceived within the inner diameter of the support catheter 200, whichcan be 0.054″, 0.070″, or 0.088″. The distal portion 615 can have areduced outer diameter compared to the payload portion 620 (see FIG. 8B)or can have a similar outer diameter as the payload portion 620 (seeFIGS. 8A and 8C). Further, the distal portion 615 can have an innerdiameter of between 0.017″ to 0.027″. The inner diameter of the distalportion 615 can allow for a procedural guidewire 805 to move freelywithin it as well as the working device 500 when it is deployed fromwithin the payload portion 620 of the microcatheter 600. Generally, theouter diameter of the microcatheter 600 has a maximum size that is lessthan 0.048 inch and an inner diameter sized to allow passage of aguidewire 805 through it.

Where the distal portion 615 is the most flexible portion of themicrocatheter 600, the proximal control element 625 of the microcatheter600 is generally the stiffest component of the entire system 700. Theproximal control element 625 can be used as a separate element forcontrolling bi-directional movement of the microcatheter 600 relative tothe procedural guidewire 805 and to the control element 510. Theproximal control element 625 of the microcatheter 600 can providesupport to push the distal portion 615 across tortuous anatomies such asthe terminal ICA from the less tortuous anatomy from the access puncturesite (e.g. common femoral artery) to the proximal common carotid or thegreat artery takeoff.

As shown in FIGS. 8B-8C, the proximal control element 625 can have areduced outer diameter compared to one or both the payload portion 620and the distal portion 615. For example, the proximal control element625 can be a spine or a hypotube or other rigid component similar towhat is described above with respect to the proximal control elements ofthe support catheter 200 and the catheter advancement element 300. As ahypotube, the proximal control element 625 allows for the guidewire 805or the control element 510 of the working device 500 to pass through itin an OTW fashion such that they extend through the single RHV 434 ofthe guide sheath 400 of the distal access system 100, as will bedescribed in more detail below. It should be appreciated, however, thatmonorail formats in which the microcatheter has two exit ports isconsidered herein as well and will be described in more detail below.

It should be appreciated that the microcatheter 600 of the deliverysystem 700 need not be spined or include a hypotube, but instead can bean intact catheter as shown in FIG. 8A. When using an intactmicrocatheter 600, the control element 510 for the working device 500may be longer than the distal access system 100. It should be similarlyappreciated, the catheter 200 of the distal access system 100 also neednot be spined and instead can be an intact catheter that has a uniforminner diameter from a proximal to distal end. The catheter 200 is shownin FIGS. 8A-8C as being spined and having a proximal control element230. The microcatheter 600 housing the working device 500 also can beadvanced through a non-spined, conventional catheter extending from theguide sheath 400.

The delivery system 700 also can be advanced through a series of nestedsupport catheters 200 providing sequential extensions in length for thedelivery system 700 to traverse. In an implementation shown in FIG. 21,a guide sheath 400 can be deployed as described elsewhere herein suchthat the distal end of the sheath 400 is advanced to a location in, forexample, the internal carotid artery (ICA). A first catheter 200 a canbe advanced through the working lumen of the guide sheath 400 and outthe distal end. The first catheter 200 a can have a distal luminalportion 222 a coupled to a proximal control element 230 a as describedelsewhere herein. The proximal control element 230 a can have a smallerouter diameter compared to the outer diameter of the distal luminalportion 222 a and can be coupled near a proximal opening from the lumenof the distal luminal portion 222 a. The first catheter 200 a can beadvanced using a catheter advancement element as described elsewhereherein. The catheter advancement element can aid the advancement of thefirst catheter 200 a through the vessel without hanging up on a severeangulation and/or a branching vessel. The first catheter 200 a can beadvanced through the working lumen of the guide sheath 400 and thenthrough the vessel to a first target location. The catheter advancementelement 300 can be removed from the lumen of the first catheter 200 a. Asecond catheter 200 b having a second catheter advancement element 300can be advanced through the lumen of the first catheter 200 a. Thesecond catheter 200 b can also include a distal luminal portion 222 bcoupled to a proximal control element 230 b near a proximal opening fromthe lumen of the distal luminal portion 222 b. Similar to the firstcatheter 200 a, the proximal control element 230 b of the secondcatheter 200 b can have a smaller outer diameter compared to the outerdiameter of the distal luminal portion 222 b. The distal end of thesecond catheter 200 b can be extended using its proximal control element230 b to extend past the distal end of the first catheter 200 a suchthat the smaller diameter second catheter 200 b can reach a target sitelocated to a distal vessel having a narrower dimension than the locationof the first catheter 200 a. In this implementation, the first spinedcatheter 200 a can act as a support catheter for the second spinedcatheter 200 b. The inner lumen of the second spined catheter 200 b canfluidly communicate with the inner lumen of the first spined catheter200 a that fluidly communicates with the working lumen of the guidesheath 400 forming a contiguous lumen formed of three sections ofincreasingly larger dimensions towards the proximal end of the cathetersystem. For example, the first catheter 200 a can have a distal luminalportion 222 a having an inner diameter of about 0.088″ and the secondcatheter 200 b can have a distal luminal portion 222 b having an innerdiameter of about 0.070″ as described elsewhere herein. It should beappreciated that more than two nested spined catheters is considered andthat their respective inner and outer diameters are sized to receive oneanother for use together. The corresponding ID and OD of the catheterscan be sized such that they slide relative to one another, but stillprovide sufficient sealing. For example, the contiguous lumens createdby the nested arrangement can seal against one another such thataspiration can be drawn through them and an appropriate pressure can beapplied through the nested catheters to accomplish, for example,aspiration force sufficient for aspiration thrombectomy of distantclots. The contiguous lumen formed by the nested catheters can be usedfor advancement of a working device 500 housed within a microcatheter600 as described elsewhere herein.

The proximal end of the nested catheter system can incorporate variousgripping, organizing, and attachment features as described elsewhereherein. For example, the guide sheath 400 can include a proximal endcoupled to a rotating hemostatic valve 434 that provides access to theworking lumen through which the catheters can be inserted. Each of thecomponents of the catheter system can extend proximally out from thevalve 434. For example, the proximal control elements 230 a, 230 b ofthe catheters 200 a, 200 b, and the proximal end of the microcatheter600 can extend through the valve 434. Proximal extensions of thecatheter advancement element (not shown in FIG. 21) can also extendproximally through the valve 434. Each of these components in thenesting or telescoping catheter set can incorporate identifying featuresat their proximal end regions that distinguish them from one another.For example, each proximal control element 230 a, 230 b can include atab 234 a, 234 b having a distinguishing shape, color, or other visualcharacteristic that is unique to that particular catheter. Each proximalcontrol element 230 a, 230 b can include a coupling feature, such as aclip or other connector, that organizes the various control elements andprevents entanglement. Nesting catheters and their respective catheteradvancement elements can be incorporated within a kit.

The term “control element” as used herein can refer to a proximal regionconfigured for a user to cause pushing movement in a distal direction aswell as pulling movement in a proximal direction. The control elementsdescribed herein can include spines, push wires, push tubes, or otherelements having any of a variety of configurations. The proximal controlelement can be a push tube in that it is hollow or tubular. The proximalcontrol element can also be solid and have no inner lumen, such as asolid rod, ribbon or other solid wire type element. Generally, theproximal control elements described herein are configured to move itsrespective component (to which it may be attached or integral) in abidirectional manner through a lumen.

As mentioned, the microcatheter 600 can be configured as anover-the-wire (OTW) device or a rapid exchange device. The OTWmicrocatheter 600 (see FIG. 8A) can allow for the guidewire 805 and/orthe control element 510 of the working device 500 (e.g. stent retriever)to enter/exit the lumen 605 of the microcatheter 600 at a proximal luer634 coupled to the proximal end of the control element 625. In the rapidexchange device, a side opening or distal wire port 604 for theguidewire 805 can be located a distance away from both the distal andproximal ends of the device 600. The distal wire port 604 can be between5-30 cm away from the distal tip of the microcatheter 600. In someimplementations, the distal wire port 604 is positioned 30-38 mm from adistal end of the microcatheter 600. In some implementations, the distalwire port 604 is located a distance between 10 cm and 20 cm from thedistal-most tip of the catheter 600.

FIGS. 12A-12B, 13A-13B, and 14A illustrate examples of a rapid exchangeversion of the microcatheter 600. As described above, the microcatheter600 can include a payload portion 620 configured to house the workingdevice 500 and a proximal control element 625 configured to manipulatethe microcatheter 600 in a bi-directional sliding manner relative to thesupport catheter 200. The distal wire port 604 for the guidewire 805 (ora side opening 606 for the working device control element 510 to exitthe lumen 605) can be located within a portion of the microcatheter 600near where the working device 500 is housed within the payload portion620 or can be located further proximal such as within the hypotubeproximal control element 625. This is compared to OTW versions in whichthe guidewire 805 and/or the control element 510 exit the proximal luer634 of the hypotube 625.

In some implementations, the proximal control element 625 is a hypotubecoupled to a proximal luer 634. The lumen of the hypotube and themicrocatheter portions can be in fluid communication with the luer 634such that distal angiographic contrast injections can be performedthrough the luer 634 out the end of the microcatheter 600. The contrastcan flow past the working device 500 housed in the payload portion 620(past the one or more ports 604, 606 in the case of a rapid exchangedevice) and primarily into the distal portion 615 of the microcatheter600.

The microcatheter 600 can transition in stiffness along its lengthsimilar to what is described above with respect to the support catheter200 and the catheter advancement element 300. The distal microcatheterportion 615 (i.e. the portion intended to extend beyond the supportcatheter 200) is the most flexible and the proximal control element 625is the stiffest part of the microcatheter 600. The proximal controlelement 625 of the microcatheter 600 can be stiffer than the stiffnessof either the distal 615 and payload portions 620 alone. The guidewire805 and control element 510 can run “side-by-side” within the proximalcontrol element 625 of the microcatheter 600 and the three componentstogether can be stiffer than even these catheter portions having theprocedural guidewire 805 and the working device control element 510extending therethrough. The stiffer proximal control element 625 canremain enclosed by the conduit formed by the lumens of the supportcatheter 200 and the guide sheath 400 such that it does not come intocontact with anatomy directly.

Because the proximal control element 625 of the microcatheter 600 hasthe greatest degree of stiffness, this portion of the device can bearthe brunt of greater pushing forces, for example, in order to deliver itacross expected tortuosity as it approaches the terminal carotid. Thiscan potentially put it at the highest risk of kinking in the system 700.The microcatheter 600 (as well as the other catheters described abovehaving a rapid exchange port) can be designed to avoid kinking andhinging near the distal wire port 604, which could create advancementproblems of the microcatheter 600. The risk for kink and bends,especially at the distal wire port 604 weak points can also be minimizedby transitioning the flexibility in the microcatheter 600 at or justdistal to the distal wire port 604. The flexibility of the microcatheter600 transitions from the distal portion 615 towards a less flexible“intermediate” catheter portion, which can include the payload portion620 as well as the distal wire port 604. Or the intermediate catheterportion can transition to the proximal control element 625 before givingrise to the distal wire port 604. The intermediate flexibility portionof the microcatheter 600 can resist kink of the distal wire port 604 ofthe procedural guidewire 805 and the proximal port 606 for the controlelement 510 of the working device 500, which will be described in moredetail below with respect to FIGS. 15-20. The distal wire port 604 canbe positioned within the stiffened intermediate portion between thedistal portion 615 and the proximal control element 625. The variablestiffness of the microcatheter 600 can be achieved in a variety of ways.

The stiffer intermediate and proximal portions of the microcatheter 600would tend to straighten cervical ICA loops and kinds of anatomy thatmay be encountered if applied directly. Thus, the stiffer portions ofthe microcatheter 600 are designed to remain within the conduit formedby the distal luminal portion 222 of the distal access catheter 200during use. As discussed above, only the distal portion 615 is intendedto extend distal to the distal access catheter 200. The overall lengthof the microcatheter 600 and the length of the spined catheter 200relative to the single RHV 434 can be designed to prevent any otherportion of the microcatheter 600 besides the flexible distal portion 615from exiting the catheter 200 to prevent straightening forces from beingimposed on the anatomy. The spined catheter 200 can be long enough thatit extends across the entire length of the cervical ICA and terminal ICAin order to reach targets as far distal as the ACA and M2 section of themiddle cerebral artery. The distal luminal portion 222 is flexible alongthat entire distance. Overall length of the microcatheter 600 can alsobe controlled to ensure the distal wire port 604 and the proximal wireport 606 on either end of the intermediate catheter portion aremaintained inside the distal luminal portion 222 of the catheter 200when expected movements are to occur. For example, when themicrocatheter 600 is most distally extended and the microcatheter 600 istraversing the terminal carotid (either with or without the distalaccess catheter 200) to the level of the ACA, M1 or M2 branches of theMCA. The distal wire port 604 thus, can remain “sleeved” when movedthereby minimizing the risk of kinking or folding of the proceduralguidewire 805 and/or control element 510 of the working device 500.

FIGS. 11A-11B show how the spined distal access catheter 200 has extremeflexibility passing through the cervical carotid extending beyond aguide sheath 400 and provides a conduit for insertion of the lessflexible components of the working device delivery system 700. Onoccasion, the tortuosity of the cervical ICA and distal carotid to thecarotid terminus can be such that the distal access only reaches thepetrous carotid (see FIG. 11B). The spined catheter 200 can be deliveredvia the guide sheath 400 (see FIG. 11B), which is typically much stifferand supportive to prevent kinking of the catheter systems from theaccess point (e.g. common femoral artery) as the takeoff of the greatvessels is approached and the carotid anatomy entered. The stiff guidesheath 400 can be placed as high as possible in the ICA. However, whencervical ICA tortuosity is present, which can be common in the elderlypopulation, then the guide sheath 400 is typically positioned below thearea of severe kink or looping to avoid straightening that segment. Inthis implementation, the length of the extremely flexible catheterportion 222 of the spined distal access catheter 200 can be at least 30cm and may be 38 cm-40 cm in length to provide sufficient overlap withthe guide sheath 400 when the catheter 200 is positioned just proximalto a severely kinked or looped cervical ICA. The length of the entirespined catheter 200 can be such that the distal luminal portion 222 isthe only portion of the device that exits the guide sheath 400, whichcan be between 80 cm-90 cm long, which still keeping some length ofoverlap for sealing. The microcatheter 600 can extend 3-5 cm beyond thedistal end of the spined catheter 200. If distal access obtained by thespined catheter 200 is to the proximal carotid, the delivery of aworking device 500 to the M2 branch may involve a microcatheter lengthextending beyond the support catheter 200 that is approximately 12 cm to15 cm. Thus, the distal portion 615 of the microcatheter 600 can beapproximately 18 cm to ensure sufficient length for accessing thesesites even if distal access obtained by the spined catheter 200 islimited. The flexibility of the distal portion 615 combined with thekink-resistance of the stiffer proximal portions of the microcatheter600 allow it to navigate independently through the bony petrous portionof the carotid and the carotid siphon and into the anterior circulationof the cerebral vascular anatomy. Generally, however, the microcatheter600 need only navigate through the conduit provided by the accesscatheter lumens.

Components of the distal access system 100 and the working devicedelivery system 700 can include one or more markers providinginformation regarding their positions relative to one another as well asrelative to the vascular anatomy. As discussed above and shown in FIG.2A, one or more radiopaque markers 411 can be disposed near a distal tip406 of the guide sheath 400. One or more radiopaque markers 224 can alsobe positioned near a distal tip of the distal access catheter 200 andone or more radiopaque markers 344 can be positioned near a distal tipof the catheter advancement element 300. The proximal control element230 of the distal access catheter 200 can include one or more markers232 as can the proximal control element 366 of the catheter advancementelement 300. The proximal control element 625 of the microcatheter 600,the proximal control element 510 of the working device 500, and theguidewire 805 can each include one or more markers along their lengthsto provide information regarding their relative positions to each otheras well as to the RHV 434 of the guide sheath 400. The specific markerscan minimize fluoroscopy use and accidental advancement of one of thecomponents beyond a desired point (e.g. the microcatheter 600 beyond thedistal tip of the catheter 200). The markers can vary in size, shape,and locations as well as be distinct from one another to provide quickand easy information regarding the component on which it is positionedand its overlap with one or more of the other components.

The distal access system 100 and the delivery system 700 can have aworking device 500 pre-loaded and housed within the lumen of themicrocatheter 600 adjacent a side opening (e.g. on a proximal side ofthe side opening) and advanced over a procedural guidewire 805. Theworking device 500 can be pre-loaded by pulling the working device 500into the distal opening at the distal tip of the microcatheter 600 andguiding the working device control element 510 out a proximal port 606in the microcatheter 600. The proximal port 606 can be located adistance proximal to where the working device 500 is housed in thepayload portion 620. The expandable payload 505 can be positionedoutside the distal opening external to the lumen 605 of themicrocatheter 600 and the proximal control element 510 extending throughthe lumen 605 and out through the proximal opening 606. The expandablepayload 505 of the working device 500 can be withdrawn or pulled intothe payload portion 620 of the microcatheter 600 until the expandablepayload of the working device 500 enters the lumen 605 through thedistal opening and slides proximally past the side opening for theguidewire 805 (i.e. the distal wire port 604) until the expandablepayload 505 is housed within the lumen 605 adjacent to the distal wireport 604 on a proximal side of the port. The procedural guidewire 805can also be back-loaded into the distal tip of the microcatheter 600 andguided to exit out the distal wire port 604 of the microcatheter 600.The distal wire port 604 through which the procedural guidewire 805extends can be located distal to the payload portion 620 housing theworking device 500 such that the procedural guidewire 805 does notextend through the payload portion 620 and the payload of the workingdevice 500. The procedural guidewire 805 can be loaded within the lumen605 of the microcatheter 600 after the expandable payload 505 ispositioned on the proximal side of the side opening 604 such that thepush wire 510 and the procedural guidewire 805 do not extendside-by-side within the lumen 605.

The proximal end of the working device control element 510 can have awire introducer or torquer 544 applied to it. Similarly, the proximalend of the guidewire 805 can have a wire introducer or torquer 844applied to it. The torquer 844 for the guidewire 805 can be discernablefrom the torquer 544 on the control element 510 of the working device500, such as by color, shape, or other identifier to allow easyidentification. The procedural guidewire 805 can be pulled intotip-to-tip position with the distal tip of the microcatheter 600 tofacilitate passage into the support catheter 200. The microcatheter 600,guidewire 805, and working device 500 can be prepped and pre-loaded inadvance and set aside until needed during a procedure, for exampleduring CT scanning (e.g. after identifying diameter and length of theworking device 500 or during patient transport), or when obtainingfemoral access. The microcatheter 600, guidewire 805, and working device500 can also be prepped simultaneous with gaining distal access andobtaining base catheter position in the internal carotid.

The microcatheter 600 pre-loaded with the working device 500 and theprocedural guidewire 805 can be advanced until the microcatheter 600extends across a target located within the intracranialneurovasculature. Pre-assembled stent retriever systems forneurovascular use in stroke treatment have never before been apossibility because the pre-loading of the stent retriever into themicrocatheter sacrificed the deliverability of the system to reach thelevels of needed to treat the stroke. However, the support catheter 200of the present system is specifically configured to navigate thetortuous neuroanatomy artificially extending the length of the guidesheath 400 and providing a complete and smooth conduit through to thetarget anatomy for ease of advancement of the pre-loaded delivery system700 that does not apply straightening forces and maintains the naturalcurvatures of the anatomy. The smooth conduit provided by the supportcatheter 200 and the guide sheath 400 means the delivery system 700 canbe pre-loaded with the working device 500.

In use and as best shown in FIGS. 9A-9I, the support catheter 200 can beinserted through a single RHV 434 coupled to a proximal end of the guidesheath 400 such that the distal luminal portion 222 extends the lengthof the catheter conduit to just the length to allow access from theaccess site entry point (e.g. the common femoral artery) to justproximal to the target for implant delivery. Use of a spined supportcatheter 200 can allow for the minimum distance to reach the target dueto the telescoping of the catheter 200 relative to the guide sheath 400.The RHV 434 can have a single head as shown in FIG. 9A or can include atwo-headed RHV as shown in FIGS. 10A-10H). After securing distal access,the operator can fix the distal access point in place with a pinch Pcreating a control point where the secured catheter 200 provides supportfor smaller catheters and wires that may be passed through it. FIG. 9Bshows the microcatheter 600 having the pre-assembled, unexpanded payload505 of the working device 500 contained within it inserted together withthe procedural guidewire 805 through this single RHV 434 of the distalaccess system 100. The three components are advanced in unison throughthe RHV 434 to advance the distal end of the microcatheter 600 very nearthe target. The microcatheter 600 and the guidewire 805 can be insertedthrough a single head of the single RHV 434 of the guide sheath 400 orthrough its own dedicated head if a two-headed RHV is being used. Atwo-headed RHV allows the support catheter 200 to be inserted throughits own dedicated port to eliminate the need to manage the catheterpositioning when working with the dedicated working channel for the IDS700. Regardless of whether the single RHV is single-headed ordual-headed, the system provides a greater ease of use compared totypical tri-axial systems in which each of the microcatheter, the distalaccess catheter and the guide sheath would be coupled to theirrespective RHVs resulting in a significantly longer system requiringmultiple operator hands to manage the multiple site of interaction. Thiscan be especially cumbersome when a two-handed maneuver is needed at oneof the RHVs (e.g. advancement of a microcatheter at an the RHV,advancing the guidewire, etc.). As mentioned above, a torquer 844 can beattached near a proximal end of both the guidewire 805 as well as thecontrol element 510 of the working device 500. In conventional tri-axialsystems, the torquers must be removed and replaced to provide grip tothe working device control element 510 as the embolus is typically veryadherent and a firm pull for movement is often needed. It should beappreciated that although the systems are described herein as beingcapable of delivery through a single RHV 434 that the more than a singleRHV can also be used as in more typical tri-axial systems.

Again with respect to FIG. 9B, advancement of the loaded IDS 700 intothe RHV 434 can include a first hand holding the RHV 434 and a secondhand grasping the proximal regions of the microcatheter 600, theguidewire 805, and the working device 500 together in a single pinch P.The arrangement of these three components can be prearranged asdescribed elsewhere herein and their juxtaposition maintained with eachthrow of the advancement through the system. Once the tip of the IDS 700reaches the distal luminal portion 222 of the spined catheter 200, theguidewire 805 can be isolated from the other components (e.g. controlelement 510 of the working device 500, proximal control element 625 ofthe microcatheter, and proximal control element 230 of the supportcatheter 200), which can be gathered into a single pinch P and heldtogether in a stationary position while the guidewire 805 is advancedindependently (see FIG. 9C). The guidewire 805 can be advanced acrossthe embolus to allow for microcatheter 600 placement. Once the guidewire805 is positioned across the target, it can be held fixed by adding theproximal region of the guidewire 805 to the pinch P holding the supportcatheter 200 while the microcatheter 600 with the working device 500housed therein are adjusted to be advanced over the guidewire (see FIG.9D). The system allows the guidewire 805 to be held fixed while themicrocatheter 600 is advanced rather than pistoning back and forth ascan occur in conventional systems.

The microcatheter 600 can reach the target across the embolus withminimal to no movement of the distal tip of the guidewire 805. FIG. 9Eshows the microcatheter 600 after the guidewire 805 is removed. Uponremoval of the guidewire 805, the proximal control element 230 of thesupport catheter 200 and the microcatheter 600 can be gathered in asingle pinch P and the control element 510 of the working device 500advanced to fix the position of the microcatheter 600 and advance theworking device 500 into position to deploy the expandable payload 505from the lumen 605 of the microcatheter 600 through the distal openingto treat the target. Thus, the working device 500 can be advanceddistally through the lumen 605 to the distal end region of themicrocatheter 600 while the microcatheter 600 and the support catheter200 are pinched together and fixed in a stationary position P. Once theexpandable payload 505 of the working device 500 is in position, thecontrol element 510 of the working device 500 and the proximal controlelement 230 of the support catheter 200 can be pinched together P andheld substantially fixed in a stationary position as the microcatheter600 is withdrawn proximally by pulling on its control element 625 at theRHV 434 (see FIG. 9F). The expandable payload 505 of the working device500 is unsheathed allowing it to deploy or expand the payload 505 at thetarget (see FIGS. 9F-9G). Once the working device 500 is unsheathed, thesingle RHV 434 can be tightened. The single RHV 434 is tightened only asingle time during the procedure in preparation for initiation ofaspiration to create a sealed system. It should also be noted that thetorquer 544 on the control element 510 of the working device 500 neednot be removed or adjusted. Following delivery of the microcatheter 600and guidewire 805 withdrawal, aspiration can be turned on at the singleRHV 434, for example, in AIS embolectomy procedures. Aspiration can beperformed before withdrawal of the working device 500 into the supportcatheter 200 and removal followed by “SMAT” with aspiration via thecatheter 200 to remove embolic debris with aspiration alone or withaspiration while withdrawing the catheter 200 by pulling on the proximalcontrol element 230. In the “Solumbra” approach, the working device 500and the distal access segment 200 can be withdrawn as a unit by pinchingP both control elements 510, 230 and pulling them out of the RHV 434 asa unit. The single RHV aspiration port 412 facilitates this with asingle-point of continuous aspiration (FIGS. 9H-9I).

The delivery systems described herein allow advancement and positioningof a triaxial system of catheters through a single RHV to deliverworking devices while avoiding the requirement of “pushing” the devicepayload 505 the entire length of the catheter delivery system 700 as istypical in conventional stent retriever systems and methods. The workingdevice payload 505 of the delivery systems 700 described herein can bepre-loaded within the microcatheter 600 such that they can be advancedin unison to the target and avoids the need for advancing the payload“bare” through the entire microcatheter length. Further, themicrocatheter 600 of the delivery systems 700 described herein can beshorter than conventional stent retriever microcatheters, which aretypically about 145 cm or longer and configured to accept stentretrievers having a push wire of 180 cm in length. For example, themicrocatheter 600 of the delivery system 700 described herein can beabout 130 cm in working length compared to conventional stent retrieversystems and in some cases between 30-50 cm shorter than conventionalsystems. This shortened length allows for the operator to work with aworking device 500 having a proximal control element 510 that issignificantly shorter than the typical stent retriever push wires and beused with a distal access system 100 that is shorter. For example, thedistal luminal portion 222 of the support catheter 200 can be between20-40 cm long and the proximal control element 230 can be between 90-100cm long. The guide sheath 400 through which the support catheter extendscan be between 80-90 cm long. When the support catheter 200 extendsbeyond the distal end of the guide sheath 400 while maintaining theoverlap 348, a channel can be created that is approximately 115 cm longfor device delivery.

A single operator can use the systems described herein by inserting thedelivery system 700 through the support catheter 200 artificiallyextending the length of the guide sheath 400 because rather than thedelivery system 700 and the support catheter 200 each having their ownRHV in addition to the RHV of the guide sheath, they are both insertedthrough the single RHV 434 on the guide sheath 400. It should beappreciated that the catheter 200 and microcatheter 600 housing theworking device payload 505 can be advanced through the same port of thesingle RHV 434 or can be advanced through separate ports of the singleRHV 434, for example, if the RHV 434 is a dual-headed RHV as shown inFIG. 10A-10H. In either scenario, whether a single channel RHV or adual-headed RHV is used, the extra RHVs are eliminated as are the extralength and extra hand movements needed to deliver the interventionaldevices. The shorter lengths of the systems described herein incombination with their insertion through a single RHV on the guidesheath provide an ease of use advantage for any operator or team ofoperators and can change a procedure from being a two-person procedureto a one-person single operator procedure. In the setting ofconventional, long stent retrievers and microcatheters, the distance thestent retriever microcatheter extends down the table and the distancethe RHV of the microcatheter extends away from a first operator requiresa second operator to manage the position of the microcatheter tomaintain hemostasis and manage any manipulations at the RHV of themicrocatheter. Conventional triaxial or quadraxial or pentaxial systemsused in stroke intervention require at least two operators.

FIGS. 10A-10H illustrate an implementation of a method using adual-headed RHV. The RHV 434 allows for the introduction of devicesthrough the sheath 400 while preventing or minimizing blood loss andpreventing air introduction into the sheath 400. The dual-headed RHV 434can include two working ports 435, 436 configured to receive one or morecomponents of the system 10. The dual-headed RHV 434 can include an arm412 that can be used as a point of aspiration during portions of theprocedure or as a line to flush the sheath 400 with saline or radiopaquecontrast. In an implementation, the first port 435 is dedicated toreceive and lock into position the control element 230 of the catheter200 and a second port 436 dedicated to receive components of thedelivery system 700 including the procedural guidewire 805. This avoidsthe need for doing this manually by a pinch during the remainder of theprocedure steps as described above. This configuration provides forbetting organization and handling of the components in the system 10while still maintaining them well within the reach of a single operator.The RHV 434 can be integral to the sheath 400 or the sheath 400 canterminate on the proximal end in a female Luer adaptor to which aseparate hemostasis valve component, such as a passive seal valve, aTuohy-Borst valve or RHV may be attached. It should be appreciated thatthe arrangement of the RHV can vary. FIGS. 10A-10H show the upper headis the “working” head and the second head is dedicated to securing thedistal access spined catheter 200 as shown elsewhere herein. This allowsthe operator to fix the distal access point in place with a “pinch” fromthe locked RHV 434. As described previously, this becomes a “controlpoint” where the secured catheter 200 provides support for smallercatheters and wires that are passed through it.

The support catheter 200 can be inserted through a port of a single RHV434 coupled to a proximal end of the guide sheath 400 such that thedistal luminal portion 222 extends the length of the catheter conduit tojust the length to allow access from the access site entry point (e.g.the common femoral artery) to just proximal to the target for implantdelivery. The proximal control element 230 of the spined catheter 200can be locked in position by the dedicated RHV 434 (see FIG. 10A). Theguidewire 805, working device 500 and microcatheter 600 can be advancedinto a separate port of the RHV 434, the “working RHV”, as a unit andadvanced to the tip of the distal access catheter 200 (see FIG. 10B).Once positioned at the distal tip of the catheter 200, the guidewire 805can be advanced independently by adjusting the “pinch” to capture boththe working device 500 and microcatheter 600 as the guidewire 805advanced across the target (see FIG. 10C).

In some implementations, a wire introducer or torquer can be placed thatallows the RHV port 436 for the working device delivery system 700 to belocked down fixing the microcatheter 600, the working device 500 and thewire introducer 644 in place. FIG. 10D shows how the wire introducer 644can be placed that allows the microcatheter 600 and working device 500to be locked down which fixed them into place. The wire introducer 644can protect the guidewire 805 from being fixed by the RHV 434 and allowfor maneuvering of the guidewire 805 using a traditionaltorque/guidewire advancement with free delivery of torque to the tip ofthe guidewire 805, which can be a pre-shaped tip. The wire introducer644 can also allow advancement and withdrawal of the guidewire 805 withthe RHV 434 fixing the microcatheter 600 and the working device 500.Once the guidewire 805 is positioned across the target, it can be heldfixed by adjusting and pinching the proximal guidewire 805 and looseningthe working RHV 434 to allow advancement of the control element 625 ofthe microcatheter 600 and the control element 510 of the working device500 together as a unit (see FIG. 10E). The action of the pinch can fixthe guidewire 805 and allows the microcatheter control element 625 andthe working device control element 510 to advance over the guidewire805. Again, any back-and-forth piston movements of the guidewire 805during delivery system 700 advancement is prevented. The microcatheter600 can be advanced safely without concern for distal guidewire trauma.The guidewire 805 can be removed once the working device 500 is inposition. The working device 500 position is fixed by pinching thecontrol element 510 together with the proximal element 230 of thesupport catheter 200 (see FIG. 10F) and unsheathed by pulling on themicrocatheter 600 (see FIG. 10G). The microcatheter 600 can be removedwhile keeping the working device 500 in place with a pinch and thenshort exchange. When the microcatheter 600 is completely removed, theRHV 434 can be tightened at both heads 436 and aspiration initiatedthrough arm 412 (FIG. 10H).

Standard stent retriever techniques call for the stent portion to befully released allowing for the struts to integrate into the embolus fora few minutes. The operator can then choose to perform a “Solumbra” or“SMAT” procedure. For example, the stent retriever can be withdrawn intothe distal access catheter 200 and removed followed by “SMAT” withaspiration via the distal catheter 200 to remove embolic debris withaspiration alone or with aspiration while withdrawing the distal accesssegment by pulling on the spined catheter 200. The SMAT approach isparticularly useful with the dual-head RHV configuration shown in FIGS.10A-10H. With the “Solumbra” approach, the stent retriever and distalaccess segment are withdrawn simultaneously by pinching both pull wires.Both pull wires can be approximated and pulled out of their closed RHVsas a unit. The Solumbra approach is particularly useful with thesingle-head RHV configuration shown in FIGS. 9A-9I.

It should be appreciated that the torquer 544 on the working device 500need not be removed or adjusted. Rather, the torquer 544 can bepositioned to be tightened should pulling of the working device 500 uponbeing embedded in the embolus require additional grip on the controlelement 510.

The relative relationships of the intact catheter delivery system 700with a stent retriever as the self-expanding payload 505 are illustratedin FIGS. 12A, 13A, and 14A. The relative relationships of the spineddelivery system 700 with a stent retriever as the self-expanding payload505 are illustrated in FIGS. 12B, 13B, and 14B. Although the workingdevice 500 is illustrated as a stent retriever it should be appreciatedthat any of a number of working devices are considered herein (e.g. flowdiverter, intracranial stent, etc.).

FIGS. 12A-12B illustrate implementations of a single operator deliverysystem 700 having an intact microcatheter 600 (FIG. 12A) or a spinedmicrocatheter 600 (FIG. 12B) for delivering the working device 500having a self-expanding payload 505. The procedural guidewire 805 canrun side-by-side with the catheter delivery system 700 and enter thelumen 605 of the microcatheter 600 at a skive or entry port 604 locatedjust distal to a point where the payload 505 is garaged within thepayload portion 620. The guidewire 805 can extend through themicrocatheter 600 near the distal region 615 and exit out the distalopening 610 of the microcatheter 600. The unexpanded payload 505 canitself be controlled in its positioning within the microcatheter 600 bythe control element 510. The control element 510 can run through thelumen 605 of the proximal length of the microcatheter 600 and out of theproximal luer 634 of the intact microcatheter 600 as shown in FIG. 12Aor exit out the proximal opening 611 from the microcatheter lumen 605 ofthe spined microcatheter 6000 as shown in FIG. 12B. The guidewire 805can enter the microcatheter 600 through the port 604 located just distalto the payload portion 620 housing the payload 505. The guidewire 805can be used to navigate across the target distal to the distal openingfrom the lumen 223 of the catheter 200 of the access system 100 and heldin place as the microcatheter 600 housing the payload 505 is advanced upto the target. In the case of the spined microcatheter 600 shown in FIG.12B, the control element 510 of the working device 500 and the controlelement 625 of the microcatheter 600 can be advanced together. Themicrocatheter 600 of the delivery system 700 can be advanced across thetarget as is typical for placement of intracranial working devices 500such as a stent retriever. The delivery system 700 can be held in placewhile the guidewire 805 is withdrawn. After guidewire 805 removal, thelumen 605 of the microcatheter 600 is free for the advancement of thepayload 505 into position across the target site. The payload 505 can beadvanced by its control element 510 while holding the microcatheter 600fixed through the lumen 605 of the microcatheter 600 from the payloadportion 620 towards the distal opening 610 and across the cerebraltarget. Once the payload 505 is visualized to be in position, themicrocatheter 600 can be removed. The payload 505 can be held fixed inposition with the control element 510 while the microcatheter 600 iswithdrawn by retracting at the RHV 634 as shown in FIG. 12A or if themicrocatheter 600 is spined as shown in FIG. 12B, at the control element625. The payload 505 is then unsheathed and allowed to self-expand asthe microcatheter 600 is removed from the system. The above sequence ofdelivery and deployment can avoid the requirement of pushing the payload505 through the entire length of a microcatheter, which runs the entirelength of the distal access system 100 having the support catheter 200extending through the guide sheath 400. Rather, the payload 505traverses only the distal portion 615 of the microcatheter 600 beforethe microcatheter 600 is withdrawn.

FIGS. 13A-13B illustrate implementations of a single operator deliverysystem 700 having an intact microcatheter 600 (FIG. 13A) or a spinedmicrocatheter 600 (FIG. 13B) for delivering a working device 500 havinga self-expanding payload 505. The procedural guidewire 805 can run theentire length of the delivery system 700. In the implementation of FIG.13A, the guidewire 805 can enter the lumen 605 of the microcatheter 600at the proximal luer 634. In the implementation of FIG. 13B, theguidewire 805 can enter the lumen 605 of the microcatheter 600 at aproximal opening 611 into the payload portion 620 of the microcatheter600 housing the expandable payload 505 in a collapsed configuration. Theguidewire 805 can extend through the self-expanding payload 505 housedwithin the payload portion 620 and exit out the distal opening 610 ofthe microcatheter. This can allow the coaxial movement of the guidewire805 through the microcatheter 600 rather than the side-by-sidepositioning seen in FIGS. 12A-12B providing better wire torque andresponsiveness. The unexpanded payload 505 can be controlled in itspositioning within the microcatheter 600 by the control element 510. Thecontrol element 510 can exit the payload portion 620 at the port 604located just proximal to the position of the expanding payload 505. Theguidewire 805 can be used to navigate across the target distal to thedistal opening from the lumen 223 of the catheter 200 of the accesssystem 100 and held in place as the microcatheter 600 housing thepayload 505 is advanced up to the target. In the case of a spinedmicrocatheter 600 shown in FIG. 13B, the control element 510 of theworking device 500 and the control element 625 of the microcatheter 600can be advanced together. The microcatheter 600 of the delivery system700 can be advanced across the target as is typical for placement ofintracranial working devices 500 such as a stent retriever. Theguidewire 805 can then be removed or the payload 505 advanced over theguidewire 805. The payload 505 can be advanced through the lumen 605 ofthe microcatheter 600 from the payload portion 620 towards the distalopening 610 after delivery of the distal microcatheter 600 across thetarget. The payload 505 can be advanced by holding the microcatheter 600fixed and advancing the payload 505 by the proximal control element 510under fluoroscopic guidance to the target. Once the payload 505 isvisualized to be in position, the microcatheter 600 can be withdrawn.The expanding payload 505 can be held fixed via the control element 510and a monorail exchange performed as the control element 510 exits theRHV 634.

FIGS. 14A-14B illustrate implementations of a single operator deliverysystem 700 having an intact microcatheter 600 (FIG. 14A) or a spinedmicrocatheter 600 (FIG. 14B) for delivering a working device 500 havinga self-expanding payload 505. The microcatheter 600 in each of theseimplementations has a step-up in outer diameter from the distal portion615 to the payload portion 620. As with previous implementations, theprocedural guidewire 805 can run the entire length of the deliverysystem 700 and in the case of FIG. 14A can enter the lumen 605 of themicrocatheter 600 at the proximal luer 634 or in the case of FIG. 14Benter the lumen 605 of the microcatheter 600 at a proximal opening 611into the payload portion 620 of the microcatheter 600 housing theexpandable payload 505 in a collapsed configuration. The guidewire 805can extend through the self-expanding payload 505 housed within thepayload portion 620 and exit out the distal opening 610 of themicrocatheter. This can allow the coaxial movement of the guidewire 805through the microcatheter 600 rather than the side-by-side positioningseen in FIGS. 12A-12B. The distal portion 615 of the microcatheter canhave a smaller outer diameter such that the payload portion 620 createsa step-up. The step-up of the payload portion 620 can allow for thecontrol element 510 that controls the positioning of the unexpandedpayload 505 within the microcatheter 600 to extend inside the lumen 605of the microcatheter 600 alongside the procedural guidewire 805 for atleast a portion or the entirety of the length of the payload portion620. In the implementation of FIG. 14A, the control element 510 can exitthe payload portion 620 at a port 604 located just proximal to theposition of the expanding payload 505. In the implementation of FIG.14B, the control element 510 can exit the payload portion 620 at theproximal opening 611. When a working device such as a stent retriever isreleased into an embolus, the expanding payload 505 embeds into theembolus and is, in turn, fixed in place. The microcatheter 600 and theguidewire 805 can be withdrawn in sequence or as a unit over the controlelement 510 with a rapid pull with minimal risk of pulling the expandingpayload 505 out of the embolus.

As mentioned above, the guidewire 805 can run through the self-expandingpayload 505 within the microcatheter 600 (see for example FIGS. 13A-13Band 14A-14B) providing the operator the sense of a coaxial relationshipand providing better wire torque and responsiveness. This coaxialrelationship can include a tool or consideration of features to thepayload 505 that would avoid catching or ensnaring the guidewire 805 tipas the system 700 is “loaded” with the guidewire 805. The tool may be asimple small tube sized to fit within the garaged payload 505 inside themicrocatheter 600 that can be removed once the guidewire 805 passagewithin the system has been confirmed. A step-up in the catheter diametermay allow for easier loading and may improve guidewire interaction.

FIGS. 12B, 13B, and 14B each illustrate the control element 510 for theworking device 500 as having a proximal wire introducer, torquer, orother gripping feature 544 making the proximal control element 510 easyto grasp, advance and/or retract. The gripping feature 544 can be easilyidentifiable or discernable from other components of the delivery system700 and/or the distal access system 100 in color and/or shape or otheridentifier or characteristic. The gripping feature 544 of the controlelement 510 can be removed prior to withdrawing the delivery system 700over the control element 510 after deployment of the working device 500.Alternatively, the control element 510 for the working device 500 neednot include any proximal gripping features allowing for a more rapiddeployment and removal such as shown in FIGS. 12A, 13A, and 14A. Thus,after placement of the distal access system 100 including the guidesheath 400 and the catheter 200 extending through the guide sheath 400and securing distal access, the operator can fix the distal access pointin place with a single hand with a pinch forming a control point wherethe secured catheter 200 provides support for the smaller catheters andwires that are passed through it. Keeping the distal catheter 200 fixedwith a pinch, the guidewire 805 can be advanced through the singleoperator delivery system 700 having the working device 500, which can behoused pre-loaded within the microcatheter 600. The guidewire 805extending through the delivery system 700 can be loaded as a unit intothe RHV 434 of the guide sheath 400 and advanced toward the end of thedistal tip of the catheter 200, the position of the catheter 200 beingheld fixed by the pinch. Once positioned at a distal tip of the catheter200, the guidewire 805 can be advanced independently by adjusting the“pinch” to capture the proximal control element 230 of the catheter 200,the proximal control element 510 of the working device 500, and theproximal control element 625 of the microcatheter 600. The systems canall be fixed with a single hand by pinching across their respectiveproximal control elements gathered together near a proximal end. Theguidewire 805 can be advanced across the target while all the controlelements are kept fixed. The guidewire 805 can then be held fixed byadding the proximal guidewire 805 to the pinch and adjusting the controlelement 625 and the control element 510 to be advanced over theguidewire 805. This sort of fixation prevents inadvertent movement ofthe guidewire tip as the delivery system 700 is advanced to the target,particularly back-and-forth piston movements, avoiding trauma andextravascular bleeding. Each of the single operator systems can be usedwhile applying distal aspiration through the support catheter 200 andthe guide sheath 400, for example, as the withdrawal of clot materialensues. In acute ischemic stroke embolectomy procedures, followingdelivery of the system 700 and withdrawal of the guidewire 805aspiration is applied at the RHV 434. Fixing the working device 500 inplace allows the payload 505 to be unsheathed by pinching the controlelement 510 and pulling on the microcatheter control element 625.Aspiration can be initiated and then an operator can choose to do a“Solumbra” or “SMAT” procedure. For example, under continuousaspiration, an operator can begin withdrawal of the working device 500by pulling on the control element 510 while keeping the catheter 200 ina fixed position therein resheathing the payload 505 into the lumen ofthe catheter 200. The working device 500 can then be removed undercontinuous aspiration with catheter 200 remaining in place or theworking device 500 and the catheter 200 can be removed together as aunit. They can be withdrawn as a unit by pinching both proximal controlelements 510 and 230. The single RHV 434 facilitates this by providing asingle-point of continuous aspiration.

It should be appreciated that the methods described herein can beperformed using a “wire first” approach wherein the guidewire isinitially placed across the target once distal access is obtainedsimilar to how coronary procedures may be performed where the guidewireleads and is preserved during the procedure. Once the guidewire isplaced across the target, the delivery system 700 having the workingdevice 500 can be prepped with the payload 505 within the proximalportion of the catheter 200 and the guidewire 805 front-loaded onto thedistal tip of the microcatheter 600 exiting a port near the distal tip.The guidewire 805 can traverse the payload 505 as well, for example,through an internal channel designed to receive the guidewire 805.

FIGS. 15A-15E illustrate various views of an implementation of a rapidexchange microcatheter for delivering a working device to theneurovasculature for the treatment of stroke. A single inner lumen 605extends through the distal end region of the microcatheter 600 from thedistal opening 610 of the microcatheter 600 to a distal guidewire port604 and further to a proximal port 606. As such, the proceduralguidewire 805 as well as the working device 500 utilize the same innerlumen 605 of the microcatheter 600. The guidewire port 604 can be a sideopening from the lumen 605 located a distance proximal to the distalopening 610. The distal guidewire port 604 can be between 5-30 cm fromthe distal tip of the microcatheter 600. In some implementations, thedistal guidewire port 604 is located about 18 cm from the distal tip ofthe microcatheter 600. The proximal port 606 can be positioned proximalto the distal guidewire port 604 such as for example, about 30 cm toabout 45 cm from the distal tip. The distal guidewire port 604 isdesigned to receive the procedural guidewire 805 to pass through itwhereas the proximal port 606 is designed to receive the proximalcontrol element 510 of the working device 500. As such, both theguidewire 805 and the working device 500 extend through the same innerlumen 605 of the microcatheter 600, but utilizing their own ports outfrom the lumen 605 located in an arrangement that prevents the guidewire805 and payload 505 of the working device 500 from interfering with oneanother.

The guidewire 805 can extend through the lumen 605 of the microcatheter600 from the distal opening 610 to the distal guidewire port 604. Theworking device 500 (e.g. a cerebral treatment device such as a stentretriever) can be loaded within the lumen 605 of the microcatheter 600,for example by withdrawing the payload 505 proximally pulling it intothe lumen 605 through the distal opening 610, such that the payload 505is garaged at a location just proximal to the side opening or distalguidewire port 604. The expandable payload 505, when loaded in themicrocatheter 600, can be housed within the lumen 605 adjacent to thedistal guidewire port 604 on a proximal side of the port 604. Theprocedural guidewire 805 can extend through the same lumen 605 of themicrocatheter 600 such that a distal end of the procedural guidewire 805extends out the distal opening 610 and a proximal end of the proceduralguidewire 805 exits the lumen 605 through the distal guidewire port 604in the wall of the microcatheter 600. The proximal control element 510of the working device 500 can extend proximally from the payload 505through the lumen 605 and exit out the proximal port 606. This preventsthe proximal control element 510 of the working device 500 and theguidewire 805 from running next to one another within the single lumen605 or needing to pass through the same entry port, which would beincompatible with rapid exchange systems.

Again with respect to FIGS. 15A-15E, the proximal port 606 can belocated near where the proximal control element 625 couples with theintermediate portion of the microcatheter 600. In some implementations,the proximal control element 625 can be a hypotube having a lumen.However, the hypotube lumen truncates to the single lumen 605 at alocation near the proximal port 606. Outer shaft tubing 670 can connectthe proximal control element 625 and a reinforced portion 652 of themicrocatheter as will be described in more detail below. A taperedmandrel extension 675 can bridge and support the outer shaft tubing 670that connects the proximal control element 625 and the reinforcedportion 652 of the microcatheter.

FIGS. 16A-16C are detail views near the distal wire port 604 ofdifferent implementations of a rapid exchange microcatheter fordelivering a working device to the neurovasculature for the treatment ofstroke. The microcatheter 600 includes reinforcement that allows themicrocatheter 600 to be advanced independently through theneurovasculature to reach target treatment locations. Without thisreinforcement, the microcatheter 600 tubing would be incapable ofnavigating through such tortuous anatomy. However, the reinforcementrequired for the microcatheter 600 to navigate the tortuous neuroanatomypresents a challenge for rapid exchange delivery in which ports throughthe wall of the microcatheter 600 are needed for the guidewire 805 andthe control element 510 to exit the lumen 605 as discussed above. Toresolve this issue, the microcatheter 600 can have a reinforcement layerformed by two independent reinforcement structures 650, 652 spaced adistance away from one another along the length of the microcatheter600. A gap G is formed between the reinforcement structures 650, 652near the location of the distal guidewire port 604. Thus, themicrocatheter 600 includes a distal, reinforced catheter portionextending between a distal end region of the catheter body to a pointnear the side opening 604 and a proximal, reinforced catheter portionextending a distance from a point near the side opening 604 towards theproximal end of the catheter body. The catheter body has a distalopening from the internal lumen near the distal-most tip and a sideopening 604 through the sidewall of the catheter body that is located adistance proximal to the distal-most tip of the catheter body. The sideopening 604 is positioned within the gap G between the proximal end ofthe distal reinforced catheter portion and a distal end of the proximal,reinforced catheter portion. The payload of a device housed within thelumen can be positioned proximal to the side opening 604. The proximal,reinforced catheter portion can be less flexible than the distal,reinforced catheter portion. The distal, reinforced catheter portion canhave a first reinforcement structure and the proximal, reinforcedcatheter portion can have a second reinforcement structure. The coupler660 can formed another reinforcement structure. The first and secondreinforcement structures can be similar or different in structure to oneanother as well as to the coupler 660. The first reinforcement structurecan be less rigid than the second reinforcement structure and the secondreinforcement structure can be less rigid than the coupler 660.

The size of the gap between the reinforcement structures 650, 652 canvary, but is generally between 3 mm-4 mm wide. The reinforcementstructures 650, 652 can be coupled together by a short, relatively rigidcoupler 660. The coupler 660 can be sized to span the gap G such thatthe elongate window of the coupler is aligned with the gap G while atleast a first portion of the coupler 660 is positioned over a proximalend of the first reinforcement structure and at least a second portionof the coupler 660 is positioned over the distal end of the secondreinforcement structure. The coupler 660 can include a side openingextending through its sidewall, such as an elongate window 654, a slit655 extending along a length of the coupler 660, or other discontinuityin its sidewall configured to align with the gap between thereinforcement structures 650, 652. The window 654 within the coupler 660forms the distal wire port 604 located within the gap G between theadjacent reinforcement structures 650, 652 of the microcatheter 600.

Generally, the microcatheter 600 can have an inner liner 656 formed of aflexible material typical of catheters, such as PTFE. The inner liner656 can be covered by the reinforcement structures 650, 652 and thereinforcement structure 650, 652, in turn, can be encased at least inpart by an outer jacket 658 formed of PEBAX or other suitable material(see FIG. 17D). The inner liner 656 and the outer jacket 658 form adual-laminate membrane encasing the coupler 660, and thus the window654. The distal wire port 604 is created by forming a slit 662 throughthe dual-laminate membrane encasing the coupler 660 at a location of thewindow 654, which will be described in more detail below.

Again with respect to FIGS. 16A-16C, the reinforcement structures 650,652 can be braided reinforcements, coiled reinforcements, or otherreinforcement structure. The structures 650, 652 can be formed of a wirehaving a particular diameter and formed into a particular pitch or PPI,as is described elsewhere herein. In some implementations, bothreinforcement structures 650, 652 are braids having a diameter/PPI thatcan be the same or different. For example, the distal reinforcementstructure 650 can be a braid having 70 PPI and the proximalreinforcement structure 652 can be a braid having 40 PPI. In otherimplementations, both reinforcement structures 650, 652 are coils havinga diameter/pitch that can be the same or different. In still furtherimplementations, a first of the reinforcement structures 650, 652 is acoil and a second of the reinforcement structures 650, 652 is a braid(see FIG. 16B). For example, the distal reinforcement structure 650 canbe a coil having a wire diameter of 0.001″ and a pitch of 0.010″ and theproximal reinforcement structure 652 can be a braid having a braid wiresize of 0.0005″×0.0025″ and a PPI of 75. In some implementations, atleast a first of the reinforcement structures 650, 652 has a wire sizeof 0.0005″×0.0015″ at a PPI of 150 along the entire length of thereinforcement. The wire size, pitch, and PPIs considered herein for thebraided or coiled reinforcement structures can vary, but are generallysuitable for transmitting sufficient torque typical for neuroaccessmicrocatheters. The reinforcement structures 650, 652 of themicrocatheter 600 can provide a tailored amount of flexibility andtorquability to achieve a balance in deliverability and accessibility.The side opening aligned with the gap G between the proximal and distalreinforcement structures 650, 652 allows for the microcatheter 600 to bedelivered in a rapid exchange manner as will be described in more detailbelow.

As mentioned, the reinforcement structures 650, 652 are coupled togetherby a relatively rigid coupler 660 having a side opening or discontinuityextending through its sidewall, such as an elongate window 654 or slit655 extending along a length of the coupler that is aligned with the gapG between the reinforcement structures 650, 652. The coupler 660provides a localized stiff portion that allows for the translation oftorque forces from the proximal reinforced end of the microcatheter 600to the distal reinforced end of the microcatheter 600 while mitigatingkinking in this area. The coupler 660 provides stiffness, but not toomuch stiffness that would also lead to kinking during the navigation ofthese tortuous regions of the neurovasculature.

The configuration of the coupler 660 can vary. In some implementations,the coupler 660 is a short tube-like structure of relatively rigidmaterial including polymers such as polyimide or PET as well as metallicmaterials such as stainless steel or the like. The length of the coupler660 can vary, but is generally between about 3 mm to about 15 mm,preferably between 8 mm-12 mm. In some implementations, the coupler 660is 7 mm long. The length of the coupler 660 is sufficient to cover atleast an end of each of the reinforcement structures 650, 652 whileleaving enough length to create the distal wire port 604 via the window654 or a slit 655 aligned with the gap G. Thus, the coupler 660 cancover at least about 1-2 mm of each reinforcement structures 650, 652 oneither end of the coupler 660 and have a region of about 3-4 mm withinwhich the window 654 or slit 655 can be located that aligns with the gapbetween the reinforcement structures 650, 652 creating the distal wireport 604. The window 654 can have a shape and dimension that varies. Insome implementations, the window 654 is about 0.015″ wide and is oval inshape. In other implementations, the coupler 660 is a discontinuous tubeand has a slit 655 extending along its length from a first end to asecond end forming a c-shaped cross-section. The coupler 660 can haveonly a window 654 (see FIGS. 17A-17D), only a slit 655 (see FIGS.18A-18C), or both a window 654 and a slit 655 (see FIGS. 19A-19C). Thecoupler 660 can additionally include one or more cut-outs 657 (e.g.radially) to provide additional flexibility to the region between thereinforcement structures 650, 652 (see FIG. 20). Depending on whetherthe coupler 660 has a window 654, slit 655, cut-outs 657, or acombination of these features, the dimensions of the material can vary.For example, in some implementations, the coupler 660 is formed of a 7mm long tube of polyimide having a single slit 655 extending along oneside, an inner diameter of about 0.023″ and a wall thickness of about0.001″. In another implementation, the coupler 660 is formed of a 7 mmlong tube of polyimide having a 3 mm window 654, a slit 655 extendingalong a backside, an inner diameter of about 0.027″ and a wall thicknessof about 0.001″. The wall thickness of the coupler 660 can be betweenabout 0.005″-about 0.002″, preferably around 0.001″. The length of thecoupler 660 and the wall thickness is selected to ensure the coupler 660is thick enough to transfer torque from the proximal reinforcementstructure 652 to the distal reinforcement structure 650 while mitigatinga kink-prone site along the length of the microcatheter 600.

As mentioned above, the coupler 660 can include a slit 655 that extendsalong its length creating a c-shaped cross-section (see FIGS. 18C and19C). The c-shaped cross-section of the coupler 660 can provide anadditional coupling effect in that it snaps down onto the end portionsof each of the reinforcement structures 650, 652 providing additionalradial compression or squeezing force down onto the components of themicrocatheter 600. The reinforcement structures 650, 652, particularlywhere they are formed of a braid, can additionally be sealed with apolymer during manufacturing that keeps the ends from unraveling (seeFIG. 16C). The polymer dabbed onto their ends aids in the meldingtogether of the components that, in combination with the radialcompression provided by the c-shaped coupler 660, provides a better sealwith the outer jacket 658.

The outer jacket 658 can be formed of a material as is known in the artsuch as a PEBAX having a Shore hardness in the range of 25D, 35D, 45D,55D, 72D depending on what part of the length of the microcatheter 600the jacket 658 covers. For example, a segment of the outer jacket 658located proximal to the coupler 660 can be formed of PEBAX having ahardness of about 72D that transitions distally to a segment of theouter jacket 658 formed of PEBAX having a hardness of about 25D. In someimplementations, the region of the microcatheter 600 distal to thecoupler 660 has an outer jacket 658 formed of PEBAX having a hardnessranging from approximately 25D to 45D, the region of the microcatheter600 proximal to the coupler 660 has an outer jacket 658 formed of PEBAXhaving a hardness of about 72D, and the region of the outer jacket 658covering the coupler 660 (and thus, the window 654) is formed of PEBAXhaving a hardness of about 55D. In some implementations, the distal mostregion of the outer jacket 658 is formed of PEBAX having a hardness ofabout 25D and can be about 5 cm in length. This distal most region cantransition proximally to a second region of the outer jacket 658 formedof PEBAX having a hardness of about 35D and can be about 6 cm in length.This second region can transition proximally to a third region of theouter jacket 658 formed of PEBAX having a hardness of about 45D and canbe about 5 cm in length. This third region can transition proximally toa fourth region of the outer jacket 658 covering the coupler 660 and thewindow 654 that is formed of PEBAX having a hardness of about 55D and isabout 6 cm in length. This fourth region can transition proximally toadditional regions of the outer jacket 658 proximal to the coupler 660that are formed of PEBAX having a hardness of about 72D.

As mentioned above, the microcatheter 600 can have an inner liner 656formed of a flexible material that is covered by a reinforcement layercut into a distal reinforcement structure 650 and a proximalreinforcement structure 652 separated a distance from the distalreinforcement structure 650 forming a gap G. The reinforcementstructures 650, 652, in turn, are encased, at least in part, by theouter jacket 658. The reinforcement structures 650, 652 are coupledtogether by the coupler 660 having a side opening or discontinuityextending through its sidewall, such as the window 654 or the slit 655,that aligns with the gap G between the reinforcement structures 650,652. The inner liner 656 and the outer jacket 658 encase the coupler 660and also the side opening (e.g. window 654 and/or slit 655). Thus, atleast at the location of the discontinuity in the coupler 660 and thegap G between the reinforcement structures 650, 652, the inner liner 656and the outer jacket 658 are in contact with one another. Where theinner liner 656 and the outer jacket 658 meet they are fused togetherforming the dual-laminate membrane at the location of the discontinuity.The distal guidewire port 604 is created by forming a slit 662 throughthe dual-laminate membrane encasing the discontinuity (e.g. window 654or slit 655 along a backside of the coupler 660). The slit 662 in thedual-laminate membrane can extend along at least a length of thediscontinuity. The distal guidewire port 604 is not merely a holethrough which devices enter and exit the lumen 605. Rather, the distalguidewire port 604 is created by the slit 662 in the dual-laminatemembrane at the location of the window 654 (or other discontinuity likethe slit 655) of the coupler 660. The distal guidewire port 604 forms aflap valve that can remain closed when not in use and that allows forthe guidewire 805 to be pushed through it. The presence of thedual-laminate membrane at the distal guidewire port 604 mitigates fluidloss from the lumen 605, for example, during injections and/oraspiration through the lumen of the catheter 600.

The flap valve-like configuration of the distal guidewire port 604 incombination with the coupler 660 also mitigates issues with the workingdevice 500 (e.g. a stent retriever) deployed from the microcatheterlumen 605 getting caught, snagged, or partially exiting the lumen 605 atthis location. Some working devices 500 such as stent retrievers havingopen-ended elements at their distal end region are likely to snag oncertain features of the microcatheter delivering the working device,such as these openings, when urged through the lumen 605 of amicrocatheter 600. The distal guidewire port 604 is selective for theguidewire 805 to exit the lumen 605 and makes these open-ended elementsof the working device 500 being delivered by the microcatheter 600 lesslikely to get caught during deployment, for example to the level of theICA to M3 anatomy. The rigidity of the coupler 660 prevents themicrocatheter 600 from bending near the location of the side opening 604making it less likely the working device 500 being delivered through thelumen of the microcatheter 600 would be urged towards the side opening604. The rigidity of the coupler 660 aided by the dual-laminate membraneencapsulating the coupler 660 mitigate risks of the open-ended devicessnagging on or being urged through the guidewire port 604 during distaladvancement.

The microcatheter 600 can be packaged having a working device 500 atleast partially inserted within the lumen 605. For example, the proximalcontrol element 510 of the working device 500 can extend through thelumen 605 and out the proximal port 606 while the payload 505 of theworking device 500 can remain outside the distal opening 610 of themicrocatheter 600. Thus, the payload 505 of the working device 500 canremain sticking out the distal end of the microcatheter 600 until theuser is ready to “garage” the payload 505 in the lumen 605 of themicrocatheter 600 at a location proximal to the distal wire port 604.Once “garaged”, the procedural guidewire 805 can freely extend throughthe lumen 605 and out the distal guidewire port 604 distal to thegaraged payload 505. It should be appreciated that the working device500 need not be pre-inserted in this manner. Additionally, the workingdevice 500 can be back-loaded into position prior to use. The proceduralguidewire 805 can be front-loaded or back-loaded prior to use as well.

The lumen 605 of the microcatheter 600 can include additional featuresto improve the likelihood that only the guidewire 805 exits the distalwire port 604 and working devices 500 garaged in the lumen 605 do not.The payload 505 of the working device 500 can be an expandable elementconfigured to change shape from a compressed configuration into anexpanded configuration after deployment from the lumen 605. A deflectoror localized thickening can be formed on an inner surface of the lumen605 just proximal to the distal guidewire port 604 such that a workingdevice 500 being deployed from the lumen 605 such as by advancing in adistal direction through the lumen 605 can be urged into a furthercompressed configuration as it is pushed past the thickening. Thisreduces the risk that open-ended components on the distal end of theworking device 500 would snag or exit out through the distal guidewireport 604. Another way to prevent open-ended stent-like working devicesfrom snagging or escaping through the window 654 is to reduce the widthof the window 654 or discontinuity in the coupler 660 to make the flapson either side of the discontinuity stiffer. The visibility in andaround the region of the distal guidewire port 604 allows the user toeasily confirm the location of the payload 505 of the working device 500relative to the port 604. For example, the working device 500 can begaraged in the microcatheter lumen 605 at a location just proximal tothe distal wire port 604. The payload 505 can be withdrawn using theproximal control element 510 thereby pulling the payload 505 into thedistal opening 610 of the microcatheter 600. The payload 505 can befurther withdrawn through the lumen 605 of the microcatheter 600 until auser visually confirms the payload 505 has been retracted proximal tothe distal guidewire port 604. This ensures the payload 505 is clear ofthe distal guidewire port 604 such that the guidewire 805 can exit/enterthe port 604 without interference with the working device 500. In someimplementations, the materials in and around the distal guidewire port604, such as the coupler 660 and the dual-laminate membrane having theslit, can be generally translucent such that a visibility region isformed. In other implementations, the color of the coupler 660 can beselected to provide high contrast between the coupler 660 and itsdiscontinuity. In some implementations, the coupler 660 is black oryellow in color.

In some implementations, the microcatheter 600 can have a translucentregion near the gap G. As best shown in FIG. 15E, the coupler 660 can becoupled to just one of the reinforcement structures (in this case, thedistal reinforcement structure 650) and to the second reinforcementstructure by virtue of a translucent coupler layer 661. The translucentcoupler layer 661 can be formed by two layers of PEBAX. The layers 661in combination with the coupler 660 can compensate for the gap inreinforcement between the reinforcement structures 650, 652 and preventkinking near the distal wire port 604. At the same time, the couplerlayer 661 can provide visualization for a working device loaded in aregion of the microcatheter lumen just proximal to the distal wireopening 604. It should be appreciated that where the microcatheter 600is described as having a coupler spanning the gap G between thereinforcement structures 650, 652 that this can include implementationsin which the gap G is spanned by the coupler 660 in combination with thetranslucent coupler layer 661.

As described herein, the microcatheter 600 can be a rapid exchangemicrocatheter that is part of a system configured for accessing theintracranial neurovasculature. The microcatheter 600 can include acatheter body having an outer diameter, an inner diameter, and adistal-most tip. The catheter body can include an internal lumen 605defined by the inner diameter and can be adapted to carry a payload 505within the internal lumen 605. The payload 505 can be delivered from theinternal lumen 605 to a target location in the intracranialneurovasculature. The inner diameter of the internal lumen 605 can besized to allow passage of a guidewire 805 and the outer diameter canhave a maximum size of less than 0.048 inches. The guidewire sideopening 604 into the internal lumen 605 is sized to allow passage of theguidewire 805 and can be located a distance between 10 cm to 20 cm fromthe distal-most tip of the catheter 600. A proximal opening 606 into theinternal lumen 605 that is different and distinct from the guidewireside opening 604 can be located a distance greater than 20 cm from thedistal-most tip. The microcatheter 600 can include a distal, reinforcedcatheter portion extending between a distal end region of the catheterbody to a point near the guidewire side opening 604 and a proximal,reinforced catheter portion extending a distance from a point near theguidewire side opening 604 towards the proximal end of the catheterbody. The guidewire side opening 604 is positioned within a gap betweena proximal end of the distal reinforce catheter portion and a distal endof the proximal, reinforced catheter portion. The system canadditionally include instructions for use that instruct a user that thepayload 505 be loaded in the internal lumen 605 at a location proximalto the guidewire side opening 604 prior to use of the catheter body. Thepayload 505 loaded in the internal lumen 605 can be at a locationproximal to the guidewire side opening 604 such that the payload 505 canbe carried within and delivered from the internal lumen 605 to a targetlocation in the intracranial neurovasculature.

Materials

One or more components of the catheters and delivery systems describedherein may be made from a metal, metal alloy, polymer, a metal-polymercomposite, ceramics, combinations thereof, and the like, or othersuitable materials. Some examples of suitable metals and metal alloysinclude stainless steel, such as 304V, 304L, and 316LV stainless steel;mild steel; nickel-titanium alloy such as linear-elastic and/orsuper-elastic nitinol; other nickel alloys such asnickel-chromium-molybdenum alloys (e.g., UNS: N06625 such as INCONEL®625, UNS: N06022 such as HASTELLOY® C-22®, UNS: N10276 such asHASTELLOY® C276®, other HASTELLOY® alloys, and the like), nickel-copperalloys (e.g., UNS: N04400 such as MONEL® 400, NICKELVAC® 400, NICORROS®400, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS:R30035 such as MP35-N® and the like), nickel-molybdenum alloys (e.g.,UNS: N10665 such as HASTELLOY® ALLOY B2®), other nickel-chromium alloys,other nickel-molybdenum alloys, other nickel-cobalt alloys, othernickel-iron alloys, other nickel-copper alloys, other nickel-tungsten ortungsten alloys, and the like; cobalt-chromium alloys;cobalt-chromium-molybdenum alloys (e.g., UNS: R30003 such as ELGILOY®,PHYNOX®, and the like); platinum enriched stainless steel; titanium;combinations thereof; and the like; or any other suitable material andas described elsewhere herein.

Implementations describe catheters and delivery systems and methods todeliver catheters to target anatomies. However, while someimplementations are described with specific regard to deliveringcatheters to a target vessel of a neurovascular anatomy such as acerebral vessel, the implementations are not so limited and certainimplementations may also be applicable to other uses. For example, thecatheters can be adapted for delivery to different neuroanatomies, suchas subclavian, vertebral, carotid vessels as well as to the coronaryanatomy or peripheral vascular anatomy, to name only a few possibleapplication. It should also be appreciated that although the systemsdescribed herein are described as being useful for treating a particularcondition or pathology, that the condition or pathology being treatedmay vary and are not intended to be limiting. Use of the terms“embolus,” “embolic,” “emboli,” “thrombus,” “occlusion,” etc. thatrelate to a target for treatment using the devices described herein arenot intended to be limiting. The terms may be used interchangeably andcan include, but are not limited to a blood clot, air bubble, smallfatty deposit, or other object carried within the bloodstream to adistant site or formed at a location in a vessel. The terms may be usedinterchangeably herein to refer to something that can cause a partial orfull occlusion of blood flow through or within the vessel.

In various implementations, description is made with reference to thefigures. However, certain implementations may be practiced without oneor more of these specific details, or in combination with other knownmethods and configurations. In the description, numerous specificdetails are set forth, such as specific configurations, dimensions, andprocesses, in order to provide a thorough understanding of theimplementations. In other instances, well-known processes andmanufacturing techniques have not been described in particular detail inorder to not unnecessarily obscure the description. Reference throughoutthis specification to “one embodiment,” “an embodiment,” “oneimplementation, “an implementation,” or the like, means that aparticular feature, structure, configuration, or characteristicdescribed is included in at least one embodiment or implementation.Thus, the appearance of the phrase “one embodiment,” “an embodiment,”“one implementation, “an implementation,” or the like, in various placesthroughout this specification are not necessarily referring to the sameembodiment or implementation. Furthermore, the particular features,structures, configurations, or characteristics may be combined in anysuitable manner in one or more implementations.

The use of relative terms throughout the description may denote arelative position or direction. For example, “distal” may indicate afirst direction away from a reference point. Similarly, “proximal” mayindicate a location in a second direction opposite to the firstdirection. However, such terms are provided to establish relative framesof reference, and are not intended to limit the use or orientation ofthe catheters and/or delivery systems to a specific configurationdescribed in the various implementations.

While this specification contains many specifics, these should not beconstrued as limitations on the scope of what is claimed or of what maybe claimed, but rather as descriptions of features specific toparticular embodiments. Certain features that are described in thisspecification in the context of separate embodiments can also beimplemented in combination in a single embodiment. Conversely, variousfeatures that are described in the context of a single embodiment canalso be implemented in multiple embodiments separately or in anysuitable sub-combination. Moreover, although features may be describedabove as acting in certain combinations and even initially claimed assuch, one or more features from a claimed combination can in some casesbe excised from the combination, and the claimed combination may bedirected to a sub-combination or a variation of a sub-combination.Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. Only a few examples and implementations are disclosed.Variations, modifications and enhancements to the described examples andimplementations and other implementations may be made based on what isdisclosed.

In the descriptions above and in the claims, phrases such as “at leastone of” or “one or more of” may occur followed by a conjunctive list ofelements or features. The term “and/or” may also occur in a list of twoor more elements or features. Unless otherwise implicitly or explicitlycontradicted by the context in which it is used, such a phrase isintended to mean any of the listed elements or features individually orany of the recited elements or features in combination with any of theother recited elements or features. For example, the phrases “at leastone of A and B;” “one or more of A and B;” and “A and/or B” are eachintended to mean “A alone, B alone, or A and B together.” A similarinterpretation is also intended for lists including three or more items.For example, the phrases “at least one of A, B, and C;” “one or more ofA, B, and C;” and “A, B, and/or C” are each intended to mean “A alone, Balone, C alone, A and B together, A and C together, B and C together, orA and B and C together.”

Use of the term “based on,” above and in the claims is intended to mean,“based at least in part on,” such that an unrecited feature or elementis also permissible.

What is claimed is:
 1. A rapid exchange microcatheter system foraccessing the intracranial neurovasculature, the microcatheter systemcomprising: (i) a catheter body having: (a) an outer diameter, an innerdiameter, and a distal-most tip; (b) an internal lumen defined by theinner diameter, the catheter body adapted to carry a payload within theinternal lumen and deliver the payload from the internal lumen to atarget location in the intracranial neurovasculature, wherein (i) theinner diameter is sized to allow passage of a guidewire and (ii) theouter diameter has a maximum size of less than 0.048 inch; (c) aguidewire side opening into the internal lumen, the guidewire sideopening sized to allow passage of a guidewire, the guidewire sideopening located a distance between 10-20 cm from the distal-most tip ofthe catheter body; (d) a proximal opening into the internal lumen, theproximal opening different and distinct from the guidewire side opening,the proximal opening located a distance greater than 20 cm from thedistal-most tip; (e) a distal, reinforced catheter portion extendingbetween a distal end region of the catheter body to a point near theguidewire side opening; and (f) a proximal, reinforced catheter portionextending a distance from a point near the guidewire side openingtowards the proximal end of the catheter body; wherein the guidewireside opening is positioned within a gap between a proximal end of thedistal reinforced catheter portion and a distal end of the proximal,reinforced catheter portion; and (ii) instructions for use that instructthat the payload be loaded in the internal lumen at a location proximalto the guidewire side opening prior to use of the catheter body.
 2. Therapid exchange microcatheter system of claim 1, wherein the proximal,reinforced catheter portion is less flexible than the distal, reinforcedcatheter portion.
 3. The rapid exchange microcatheter system of claim 1,wherein the distal, reinforced catheter portion has a firstreinforcement structure.
 4. The rapid exchange microcatheter system ofclaim 3, wherein the proximal, reinforced catheter portion has a secondreinforcement structure.
 5. The rapid exchange microcatheter system ofclaim 4, wherein the first reinforcement structure is coupled to thesecond reinforcement structure by a rigid coupler.
 6. The rapid exchangemicrocatheter system of claim 4, wherein the first and secondreinforcement structure are different in structure to one another. 7.The rapid exchange microcatheter system of claim 4, wherein the firstreinforcement structure is a coil and the second reinforcement structureis a coil, wherein a pitch of the coil of the first reinforcementstructure is greater than a pitch of the coil of the secondreinforcement structure.
 8. The rapid exchange microcatheter system ofclaim 5, wherein the coupler has a window aligned with the side opening.9. The rapid exchange microcatheter system of claim 1, wherein asidewall of the catheter body comprises: a lubricious, tubular liner; areinforcement layer positioned over the tubular liner that is more rigidthan the tubular liner, the reinforcement layer comprising: a firstreinforcement structure extending within the distal, reinforced catheterportion, the first reinforcement structure having a proximal end; and asecond reinforcement structure extending within the proximal, reinforcedcatheter portion, the second reinforcement structure having a distalend, wherein the proximal end of the first reinforcement structure isseparated from the distal end of the second reinforcement structurecreating the gap; a short, tubular rigid coupler positioned over theproximal end of the first reinforcement structure and over the distalend of the second reinforcement structure, the coupler having anelongate window extending through a sidewall of the coupler; and anouter jacket positioned over the coupler and the reinforcement layer.10. A rapid exchange microcatheter system for accessing the intracranialneurovasculature, the microcatheter system comprising: (i) a catheterbody having: (a) an outer diameter, an inner diameter, and a distal-mosttip; (b) an internal lumen defined by the inner diameter, the catheterbody adapted to carry a payload within the internal lumen and deliverthe payload from the internal lumen to a target location in theintracranial neurovasculature, wherein (i) the inner diameter is sizedto allow passage of a guidewire and (ii) the outer diameter body has amaximum size of less than 0.048 inch; (c) a guidewire side opening intothe internal lumen, the guidewire side opening sized to allow passage ofa guidewire, the guidewire side opening located a distance between 10-20cm from the distal-most tip of the catheter body; (d) a proximal openinginto the internal lumen, the proximal opening different and distinctfrom the guidewire side opening, the proximal opening located a distancegreater than 20 cm from the distal-most tip; (e) a distal, reinforcedcatheter portion extending between a distal end region of the catheterbody to a point near the guidewire side opening; and (f) a proximal,reinforced catheter portion extending a distance from a point near theguidewire side opening towards the proximal end of the catheter body;wherein the guidewire side opening is positioned within a gap between aproximal end of the distal reinforced catheter portion and a distal endof the proximal, reinforced catheter portion; and (ii) the payloadloaded in the internal lumen at a location proximal to the guidewireside opening such that the payload can be carried within and deliveredfrom the internal lumen to a target location in the intracranialneurovasculature.
 11. The rapid exchange microcatheter system of claim10, wherein the proximal, reinforced catheter portion is less flexiblethan the distal, reinforced catheter portion.
 12. The rapid exchangemicrocatheter system of claim 10, wherein the distal, reinforcedcatheter portion has a first reinforcement structure.
 13. The rapidexchange microcatheter system of claim 12, wherein the proximal,reinforced catheter portion has a second reinforcement structure. 14.The rapid exchange microcatheter system of claim 13, wherein the firstreinforcement structure is coupled to the second reinforcement structureby a rigid coupler.
 15. The rapid exchange microcatheter system of claim13, wherein the first and second reinforcement structure are differentin structure to one another.
 16. The rapid exchange microcatheter systemof claim 13, wherein the first reinforcement structure is a coil and thesecond reinforcement structure is a coil, wherein a pitch of the coil ofthe first reinforcement structure is greater than a pitch of the coil ofthe second reinforcement structure.
 17. The rapid exchange microcathetersystem of claim 14, wherein the coupler has a window aligned with theside opening.
 18. The rapid exchange microcatheter system of claim 10,wherein a sidewall of the catheter body comprises: a lubricious, tubularliner; a reinforcement layer positioned over the tubular liner that ismore rigid than the tubular liner, the reinforcement layer comprising: afirst reinforcement structure extending within the distal, reinforcedcatheter portion, the first reinforcement structure having a proximalend; and a second reinforcement structure extending within the proximal,reinforced catheter portion, the second reinforcement structure having adistal end, wherein the proximal end of the first reinforcementstructure is separated from the distal end of the second reinforcementstructure creating the gap; a short, tubular rigid coupler positionedover the proximal end of the first reinforcement structure and over thedistal end of the second reinforcement structure, the coupler having anelongate window extending through a sidewall of the coupler; and anouter jacket positioned over the coupler and the reinforcement layer.